Exhibit 99.1

FOR IMMEDIATE RELEASE

        DATE: January 30, 2013

HERITAGE FINANCIAL ANNOUNCES FOURTH QUARTER AND FULL YEAR 2012 RESULTS AND DECLARES CASH DIVIDEND

Olympia, WA - HERITAGE FINANCIAL CORPORATION (NASDAQ GS: HFWA) Brian L. Vance, President and CEO of Heritage Financial Corporation (“Company” or “Heritage”), today reported that the Company had net income of $3.0 million for the quarter ended December 31, 2012 compared to net income of $2.2 million for the quarter ended December 31, 2011 and $2.9 million for the linked-quarter ended September 30, 2012. Net income for the quarter ended December 31, 2012 was $0.20 per diluted common share compared to $0.14 per diluted common share for the quarter ended December 31, 2011 and $0.19 per diluted common share for the linked-quarter ended September 30, 2012.

Net income for the year ended December 31, 2012 was $13.3 million, or $0.87 per diluted common share, compared to $6.5 million, or $0.42 per diluted common share, for the year ended December 31, 2011.

Mr. Vance commented, “2012 was a good year for Heritage and we are entering 2013 with a strong balance sheet, good profitability and solid credit metrics. Our return on average assets for 2012 was 0.98%. I believe this performance is noteworthy considering the net interest margin compression our industry continues to experience.”

“We also announced the acquisition of Northwest Commercial Bank in September 2012 which closed on January 9^th of this year. We feel we are well-positioned to continue to take advantage of opportunities as they arise.”

“Another important event during this past quarter was the addition of Ann Watson to our Board. Ann has a strong background of executive-level experience in the financial services industry. We are fortunate to add Ann and her expertise to our experienced and competent Board.”

Balance Sheet

The Company’s total assets decreased to $1.35 billion at December 31, 2012 from $1.37 billion at both September 30, 2012 and December 31, 2011. The decrease from prior periods was primarily due to decreases in purchased loans, net of allowance for loan losses, and decreases in interest earning deposits.

Total originated loans (not including loans held for sale) increased $2.5 million to $874.5 million at December 31, 2012 from $872.0 million at September 30, 2012 and increased $36.6 million from $837.9 million at December 31, 2011. The increases were due primarily to increases in commercial business loans.

Total deposits decreased $15.7 million to $1.12 billion at December 31, 2012 from $1.13 billion at September 30, 2012. Total non-maturity deposits decreased $9.5 million to $829.0 million at December 31, 2012 from $838.6 million at September 30, 2012 and certificates of deposit decreased $6.2 million to $288.9 million at December 31, 2012 from $295.1 million at September 30, 2012. Non-maturity deposits to total deposits increased to 74.2% at December 31, 2012 from 74.0% at September 30, 2012 and from 71.0% at December 31, 2011. In addition, noninterest demand deposits to total deposits increased to 22.1% at December 31, 2012 from 22.0% at September 30, 2012 and from 20.4% at December 31, 2011.

Total equity decreased $3.3 million to $198.9 million at December 31, 2012 from $202.2 million at September 30, 2012. The decrease was primarily due to $5.8 million in cash dividends and $745,000 in stock repurchases partially offset by $3.0 million in net income. During the quarter ended December 31, 2012, the Company repurchased approximately 54,000 shares at a weighted average price per share of $13.87. For the year ended December 31, 2012, the Company repurchased approximately 446,000 shares at a weighted average price per share of $13.51. The Company and its subsidiary banks continue to maintain capital levels significantly in excess of the applicable regulatory requirements for them to be categorized as “well-capitalized”. The Company had Tier 1 leverage, Tier 1 risk-based and total risk-based capital ratios at December 31, 2012 of 13.6%, 18.7%, and 19.9%, respectively, as compared to 14.0%, 19.1% and 20.4% at September 30, 2012, respectively.

Mr. Vance continued, “As noted in this release, the increases in originated loans occurred primarily in the commercial business loans sector. The economy continues to grow at a slow pace and organic loan growth will continue to be a challenge going forward.”

“During 2012, we returned $12.2 million ($0.80 per share) to our shareholders in the form of regular and special cash dividends in addition to repurchasing $6.0 million of common stock. We will continue to manage our capital using a variety of strategies and executing on our growth initiatives in order to bring our capital to more normalized levels.”

Credit Quality

The allowance for loan losses on originated loans decreased $1.4 million to $19.1 million at December 31, 2012 from $20.5 million at September 30, 2012 as a result of $1.7 million of net charge-offs recognized during the quarter. Nonperforming originated loans to total originated loans decreased to 1.28% at December 31, 2012 from 1.57% at September 30, 2012. Nonaccrual originated loans decreased $3.2 million to $12.5 million ($11.3 million net of government agency guarantees) at December 31, 2012 from $15.7 million ($13.7 million net of governmental guarantees) at September 30, 2012. The decrease in nonaccrual loans was due to $2.0 million of principal reductions, $765,000 of charge-offs and $844,000 in transfers to other real estate owned partially offset by $343,000 in additions to nonaccrual originated loans.

The allowance for loan losses to nonperforming originated loans was 170.44% at December 31, 2012 compared to 149.94% at September 30, 2012. Potential problem originated loans were $28.3 million at December 31, 2012, a decrease of $1.1 million from $29.4 million at September 30, 2012. Restructured originated performing loans were $15.0 million at December 31, 2012 compared to $15.3 million at September 30, 2012. The Company believes that its allowance for loan losses is appropriate to provide for probable incurred losses based on an evaluation of known and inherent risks in the loan portfolio at December 31, 2012.

Nonperforming originated assets were $17.9 million ($16.6 million net of government agency guarantees), or 1.39% of total originated assets, at December 31, 2012, compared to $22.7 million ($20.7 million net of government agency guarantees), or 1.72% of total originated assets, at September 30, 2012. Other real estate owned decreased to $5.7 million at December 31, 2012 (of which $260,000 was covered by Federal Deposit Insurance Corporation (“FDIC”) loss sharing agreements) from $7.3 million at September 30, 2012 (of which $260,000 was covered by

FDIC loss sharing agreements). The decrease in other real estate owned was due to the disposition of 10 properties with an aggregate carrying value of totaling $2.7 million partially offset by the addition of eight properties totaling $1.4 million. During the quarter ended December 31, 2012, the Company recognized a net gain of $588,000 on the disposition of the 10 properties partially offset by a $341,000 valuation adjustment of one property.

Mr. Vance added, “Our nonperforming originated assets to total originated assets stand at 1.39% down from 2.14% a year ago and 1.72% last quarter. Our allowance for loan losses to total originated loans stands at a very healthy 2.19%. We realize our overall loan loss allowance has slowly decreased which is in direct and expected correlation to the steady improvement in overall nonperforming loans. However, our allowance to nonperforming loans has steadily increased and now stands at a very strong 170%.”

Operating Results

Net interest income decreased $771,000, or 4.7%, to $15.7 million for the quarter ended December 31, 2012 compared to $16.5 million for the same period in 2011. Net interest income decreased $3.0 million, or 4.4%, to $64.6 million for the year ended December 31, 2012 compared to $67.5 million during the same period in the prior year. The decrease in net interest income is primarily due to the decline in net interest margins during the respective periods.

Heritage’s net interest margin for the quarter ended December 31, 2012 decreased 20 basis points to 4.98% from 5.18% for the same period in 2011 and 12 basis points from 5.10% in the linked-quarter ended September 30, 2012. The net interest margin for the year ended December 31, 2012 decreased to 5.17% from 5.41% in the same period in 2011. The decline in net interest margin is due to a combination of lower contractual note rates and the overall lessening impact of discount accretion on the acquired loan portfolios.

The effect on the net interest margin of discount accretion on the acquired loan portfolios for the quarter ended December 31, 2012 was approximately 48 basis points compared to 43 basis points in the same quarter of the prior year and 49 basis points for the linked-quarter ended September 30, 2012. The effect on the net interest margin of discount accretion on the acquired loan portfolios for the year ended December 31, 2012 was approximately 50 basis points compared to 63 basis points for the year ended December 31, 2011. Interest reversals on nonaccrual originated loans impacting the net interest margin for the quarter ended December 31, 2012 were approximately six basis points compared to nine basis points for the same quarter in the prior year and six basis points for the linked-quarter ended September 30, 2012. Interest reversals on nonaccrual originated loans impacting the net interest margin for the year ended December 31, 2012 were approximately seven basis points compared to 11 basis points for the prior year ended December 31, 2011.

The provision for loan losses on originated loans was $280,000 for the quarter ended December 31, 2012 compared to $195,000 for the quarter ended December 31, 2011. For the year ended December 31, 2012, the provision for loan losses on originated loans decreased $4.5 million to $695,000 from $5.2 million for the year ended December 31, 2011. The decrease in the year-to-date provision expense was substantially due to improving credit quality metrics, such as the decrease in ratio of nonperforming originated loans to total originated loans as noted above. The Company had net charge-offs on originated loans of $1.7 million for the quarter ended December 31, 2012 compared to $525,000 for the quarter ended September 30, 2012 and $265,000 for the quarter ended December 31, 2011. For the year ended December 31, 2012, the Company had net charge-offs on originated loans of $3.9 million compared to $4.9 million for the year ended December 31, 2011.

The provision for loan losses on purchased loans totaled $419,000 for the quarter ended December 31, 2012 compared to $3.1 million for the comparable period in the prior year and $592,000 for the linked-quarter ended September 30, 2012. For the year ended December 31, 2012, the provision for loan losses on purchased loans was $1.3 million compared to $9.3 million for the year ended December 31, 2011. As of the acquisition dates, purchased loans were recorded at their estimated fair value, incorporating our estimate of future expected cash flows until the ultimate resolution of these credits. To the extent actual or projected cash flows are less than previously estimated, additional provisions for loan losses on the purchased loan portfolios will be recognized immediately into earnings. To the extent actual or projected cash flows are more than previously estimated, the increase in cash flows is recognized immediately as a recapture of provision for loan losses up to the amount of any provision previously recognized for that pool of loans, if any, then prospectively recognized in interest income as a yield adjustment.

Cash flows on pools of acquired loans are re-estimated on a quarterly basis. As reflected in the table below, incremental accretion income was $1.5 million for both the quarters ended December 31, 2012 and September 30, 2012 and $1.4 million for the quarter ended December 31, 2011. For the year ended December 31, 2012, incremental accretion income was $6.3 million compared to $7.9 million for the year ended December 31, 2011.

For the quarter ended December 31, 2012, the Company recognized $(346,000) of change in the FDIC indemnification asset compared to $(492,000) and $327,000 for the quarters ended September 30, 2012 and December 31, 2011, respectively. For the year ended December 31, 2012, the Company recognized $(1.0) million of change in the FDIC indemnification asset compared to $(2.3) million for the year ended December 31, 2011.

The following table illustrates the significant accounting entries associated with the Company’s acquired loan portfolios:

Donald J. Hinson, Executive Vice President and Chief Financial Officer, commented, “Our net interest margin was a very strong 4.98% for the quarter ended December 31, 2012. However, due to the low rate environment, we expect to see a continuing trend of declining net interest margins as a result of ongoing downward pressure on loan and investment yields.”

Noninterest income was $1.8 million for the quarter ended December 31, 2012 compared to $2.3 million for the same period in 2011 and $1.5 million for the linked-quarter ended September 30, 2012. For the year ended December 31, 2012, noninterest income increased $1.5 million to $7.3 million from $5.7 million for the year ended December 31, 2011. The variances in noninterest income from prior periods are primarily due to the change in the FDIC indemnification asset.

Noninterest expense was $12.4 million for the quarter ended December 31, 2012 compared to $12.3 million for the quarter ended December 31, 2011 and $12.5 million for the linked-quarter ended September 30, 2012. The increase for the quarter ended December 31, 2012 compared to same period in 2011 was primarily due to increases in salaries and benefits of $409,000. The slight decrease from the linked-quarter ended September 30, 2012 was primarily due to gains on sales of other real estate owned as noted above. Noninterest expense increased $689,000, or 1.4%, to $50.4 million for the year ended December 31, 2012 compared to $49.7 million for the year ended December 31, 2011. The increase was due primarily to increases of $1.9 million in salaries and employee benefits and $481,000 in professional services, partially offset by decreases of $605,000 in other real estate owned expense and $556,000 in federal deposit insurance premium expense.

Income tax expense was $1.3 million for the quarter ended December 31, 2012 compared to $1.0 million for the comparable quarter in 2011 and $1.3 million for the linked-quarter ended September 30, 2012. For the year ended December 31, 2012, income tax expense was $6.2 million compared to $2.6 million for the year ended December 31, 2011. The increases in income tax expense from prior periods were primarily due to respective increases in pre-tax income.

Dividend

On January 30, 2013, the Company’s Board of Directors declared a quarterly cash dividend of $0.08 per common share payable on February 22, 2013 to shareholders of record on February 8, 2013.

Earnings Conference Call

The Company will hold a telephone conference call to discuss this earnings release on January 31, 2013 at 11:00 a.m. Pacific time. To access the call, please dial (800) 230-1074 a few minutes prior to 11:00 a.m. Pacific time. The call will be available for replay through February 12, 2013, by dialing (800) 475-6701 — access code 277667.

About Heritage Financial

Heritage Financial Corporation is a bank holding company headquartered in Olympia, Washington. The Company operates two community banks, Heritage Bank and Central Valley Bank. Heritage Bank serves western Washington and the greater Portland, Oregon area through its twenty-nine full-service banking offices and its Online Banking Website www.HeritageBankNW.com. Central Valley Bank serves Yakima and Kittitas counties in central Washington through its six full-service banking offices and its Online Banking Website www.CVBankWA.com. Additional information about Heritage Financial Corporation is available on its Internet Website www.HF-WA.com.

Contact:

Brian L. Vance, President & Chief Executive Officer, (360) 943-1500

Donald J. Hinson, Executive Vice President & Chief Financial Officer, (360) 943-1500

Non-GAAP Financial Measures

This news release contains certain non-GAAP financial measures in addition to results presented in accordance with Generally Accepted Accounting Principles (GAAP). These measures include tangible common equity, tangible book value per share and tangible common equity to tangible assets. Tangible common equity (tangible book value) excludes goodwill and other intangible assets. Tangible assets exclude goodwill and other intangible assets. Management has presented these non-GAAP financial measures in this earnings release because it believes that they provide useful and comparative information to assess trends in the Company’s capital reflected in the current quarter and year-to-date results. Where applicable, the Company has also presented comparable capital information using GAAP financial measures. Reconciliations of the GAAP and non-GAAP financial measures are presented below.

Forward-Looking Statements

“Safe Harbor” statement under the Private Securities Litigation Reform Act of 1995: This release contains forward-looking statements that are subject to risks and uncertainties, including, but not limited to: the credit risks of lending activities, including changes in the level and trend of loan delinquencies and write-offs and changes in our allowance for loan losses and provision for loan losses that may be impacted by deterioration in the housing and commercial real estate markets; changes in general economic conditions, either nationally or in our market areas; changes in the levels of general interest rates, and the relative differences between short and long term interest rates, deposit interest rates, our net interest margin and funding sources; fluctuations in the demand for loans, the number of unsold homes and other properties and fluctuations in real estate values in our market areas; results of examinations of us by the Board of Governors of the Federal Reserve System and of our bank subsidiaries by the Federal Deposit Insurance Corporation, the Washington State Department of Financial Institutions, Division of Banks or other regulatory authorities, including the possibility that any such regulatory authority may, among other things, require us to increase our allowance for loan losses, write-down assets, change our regulatory capital position or affect our ability to borrow funds or maintain or increase deposits, or impose additional requirements and restrictions on us, any of which could adversely affect our liquidity and earnings; legislative or regulatory changes that adversely affect our business including changes in regulatory policies and principles, including the interpretation of regulatory capital or other rules including changes related to Basel III; the impact of the Dodd-Frank Wall Street Reform and Consumer Protection Act and the implementing regulations; our ability to control operating costs and expenses; the use of estimates in determining fair value of certain of our assets, which estimates may prove to be incorrect and result in significant declines in valuation; difficulties in reducing risk associated with the loans on our balance sheet; staffing fluctuations in response to product demand or the implementation of corporate strategies that affect our workforce and potential associated charges; computer systems on which we depend could fail or experience a security breach; our ability to retain key members of our senior management team; costs and effects of litigation, including settlements and judgments; our ability to implement our expansion strategy; our ability to successfully integrate any assets, liabilities, customers, systems, and management personnel we have acquired including the Cowlitz Bank and Pierce Commercial Bank transactions, or may in the future acquire into our operations, including the recent acquisition of Northwest Commercial Bank and our ability to realize related revenue synergies and cost savings within expected time frames and any goodwill charges related thereto; risks relating to acquiring assets or entering markets in which we have not previously operated and may not be familiar; changes in consumer spending, borrowing and savings habits; the availability of resources to address

changes in laws, rules, or regulations or to respond to regulatory actions; adverse changes in the securities markets; inability of key third-party providers to perform their obligations to us; changes in accounting policies and practices, as may be adopted by the financial institution regulatory agencies or the Financial Accounting Standards Board, including additional guidance and interpretation on accounting issues and details of the implementation of new accounting methods; other economic, competitive, governmental, regulatory, and technological factors affecting our operations, pricing, products and services; and other risks detailed from time to time in our filings with the Securities and Exchange Commission.

The Company cautions readers not to place undue reliance on any forward-looking statements. Moreover, you should treat these statements as speaking only as of the date they are made and based only on information then actually known to the Company. The Company does not undertake and specifically disclaims any obligation to revise any forward-looking statements to reflect the occurrence of anticipated or unanticipated events or circumstances after the date of such statements. These risks could cause our actual results for future periods to differ materially from those expressed in any forward-looking statements by, or on behalf of, us, and could negatively affect the Company’s operating and stock price performance.

HERITAGE FINANCIAL CORPORATION

CONDENSED CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION

(Dollar amounts in thousands; unaudited)

HERITAGE FINANCIAL CORPORATION

CONDENSED CONSOLIDATED STATEMENTS OF INCOME

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HERITAGE FINANCIAL CORPORATION

FINANCIAL STATISTICS

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HERITAGE FINANCIAL CORPORATION

FINANCIAL STATISTICS

(Dollar amounts in thousands; unaudited)

HERITAGE FINANCIAL CORPORATION

FINANCIAL STATISTICS

(Dollar amounts in thousands, except per share amounts; unaudited)