Exhibit 99.1

FOR IMMEDIATE RELEASE

Heidrick & Struggles Reports First Quarter 2015 Financial Results

CHICAGO – April 28, 2015 - Heidrick & Struggles, a premier provider of senior-level Executive Search, Leadership Consulting and Culture Shaping services globally, today announced financial results for its first quarter ended March 31, 2015.

Consolidated net revenue (revenue before reimbursements) increased 3.6 percent, or $4.0 million, to $115.2 million from $111.1 million in the 2014 first quarter. Exchange rate fluctuations negatively impacted results by $4.9 million, or approximately 4 percent.

Executive Search and Leadership Consulting net revenue increased 2.3 percent year over year, or $2.4 million, to $107.0 million. The improvement was driven by a 12.0 percent increase in the Americas and a 10.1 percent increase in Asia Pacific (16.5 percent on a constant currency basis), partially offset by a 25.0 percent decline in Europe (13.5 percent decline on a constant currency basis). From a global practices perspective, the Financial Services and Industrial industry practices were the primary drivers of year-over-year growth.

Net revenue from Culture Shaping services increased 24.6 percent, or $1.6 million, to $8.1 million from $6.5 million in the 2014 first quarter. The improvement in net revenue primarily reflects a higher volume of client work in the quarter.

“Revenue growth and an increase in profitability underscore a solid first quarter for the firm globally,” said Tracy R. Wolstencroft, Heidrick & Struggles’ President and Chief Executive Officer. “We are pleased with the improved results in our Americas and Asia Pacific regions, and in our Culture Shaping business. Europe experienced a slower than anticipated start to 2015, in addition to being impacted by foreign currency exchange rates.”

The company ended the first quarter with 323 Executive Search and Leadership Consulting consultants compared to 303 at March 31, 2014 and 307 at December 31, 2014. Productivity, as measured by annualized Executive Search and Leadership Consulting net revenue per consultant, was $1.4 million in the 2015 first quarter, the same as in the 2014 first quarter. Specific to Executive Search, the company’s largest business, the number of confirmed searches in the 2015 first quarter increased 2.0 percent compared to the 2014 first quarter, while the average revenue per executive search was $102,700 compared to $101,200 in the 2014 first quarter.

Salaries and employee benefits expense in the 2015 first quarter increased 3.4 percent, or $2.6 million, to $78.5 million from $75.9 million in the 2014 first quarter. Variable compensation expense increased $2.0 million, primarily related to improved company performance, and fixed compensation expense increased $0.6 million. Salaries and employee benefits expense was 68.1 percent of net revenue for the quarter, compared to 68.3 percent in the 2014 first quarter.

General and administrative expenses declined 12.8 percent, or $4.4 million, to $30.0 million from $34.4 million in the 2014 first quarter. The decrease primarily reflects lower professional services fees, a decline in internal travel-related expenses, and the absence of a tax-related matter in last year’s first quarter. As a percentage of net revenue, general and administrative expenses were 26.1 percent compared to 31.0 percent in the 2014 first quarter.

Adjusted EBITDA⁽¹⁾ in the 2015 first quarter improved to $12.3 million, compared to $6.0 million in the 2014 first quarter. The Adjusted EBITDA margin (Adjusted EBITDA as a percentage of net revenue) in the 2015 first quarter was 10.7 percent, compared to 5.4 percent in the 2014 first quarter. The year-over-year improvements reflect higher net revenue and a decline in general and administrative expenses, partially offset by the increase in salaries and employee benefits expense.

Operating income in the 2015 first quarter increased by $5.9 million to $6.7 million, and operating margin (operating income as a percentage of net revenue) improved to 5.8 percent. This compares to operating income of $0.8 million and operating margin of 0.7 percent in the 2014 first quarter.

Net income in the 2015 first quarter was $3.4 million and diluted earnings per share were $0.18, based on an effective tax rate of 47.5 percent in the quarter and a full-year projected tax rate of approximately 41 percent. In the 2014 first quarter, the company reported a net loss of $0.7 million and a net loss per share of $0.04 after recording $1.3 million of income tax expense based on a full-year projected tax rate of approximately 51 percent.

Net cash used by operating activities in the 2015 first quarter, which includes annual bonus payments, was $87.8 million, compared to $74.9 million in the 2014 first quarter. Following the payment of bonuses, cash and cash equivalents were $107.6 million at March 31, 2015 ($79.6 million net of debt) compared to $211.4 million at December 31, 2014 ($181.9 million net of debt) and $101.4 million at March 31, 2014 ($67.4 million net of debt).

Second Quarter 2015 Outlook

The company is forecasting second quarter 2015 consolidated net revenue of between $127 million and $137 million. This forecast is based on the average currency rates in March 2015 and reflects, among other factors, management’s assumptions for the anticipated volume of new Executive Search confirmations, Leadership Consulting assignments and Culture Shaping services, the current backlog, consultant productivity, consultant retention, and the seasonality of its business.

“We are adding to the talent base of our firm,” Wolstencroft added. “Through a combination of hiring initiatives, annual promotions and lower turnover, our worldwide consultant base increased by almost seven percent year over year at the end of the first quarter. As important, we have doubled our training and development budget to ensure the success of our new consultants. We’ll continue to invest capital to attract and retain the best consultants in the world and to expand our service offerings so that Heidrick & Struggles is enabled to provide increasing value to our clients as a trusted leadership advisory firm.”

Quarterly Conference Call

Executives of Heidrick & Struggles will host a conference call to review its first quarter 2015 results today, April 28, at 9 a.m. Central Time. Participants may access the company’s call and supporting slides through its website at www.heidrick.com. For those unable to participate on the live call, a webcast and copy of the slides will be archived at www.heidrick.com and available for up to 30 days following the investor call.

About Heidrick & Struggles International, Inc.

Heidrick & Struggles (Nasdaq: HSII) is a premier provider of senior-level Executive Search, Culture Shaping and Leadership Consulting services. For more than 60 years, we have helped our clients build strong leadership teams through quality service, deep insights and our relationships with talented individuals worldwide. Today, Heidrick & Struggles’ leadership experts operate from principal business centers in North America, Latin America, Europe, Asia Pacific, Africa and the Middle East. For more information about Heidrick & Struggles, please visit www.heidrick.com.

Non-GAAP Financial Measures

This earnings release contains certain non-GAAP financial measures. A “non-GAAP financial measure” is defined as a numerical measure of a company’s financial performance that excludes or includes amounts different than the most directly comparable measure calculated and presented in accordance with GAAP in the statements of comprehensive income, balance sheets or statements of cash flow of the company. Pursuant to the requirements of Regulation G, this earnings release contains the most directly comparable GAAP financial measure to the non-GAAP financial measure.

The non-GAAP financial measures used within this earnings release are Adjusted EBITDA and Adjusted EBITDA margin. Adjusted EBITDA refers to earnings before interest, taxes, depreciation, intangible amortization, stock-based compensation expense, compensation expense associated with Senn Delaney retention awards, earnout accretion expense related to acquisitions, restructuring charges, and other non-operating income (expense). Adjusted EBITDA margin refers to Adjusted EBITDA (as explained above) as a percentage of net revenue in the same period. A reconciliation of Adjusted EBITDA to Net Income is provided on the last page of this release.

These measures are presented because management uses this information to monitor and evaluate financial results and trends. Management believes this information is also useful for investors.

Safe Harbor Statement

This press release contains forward-looking statements. The forward-looking statements are based on current expectations, estimates, forecasts and projections about the industry in which we operate and management’s beliefs and assumptions. Forward-looking statements may be identified by the use of words such as “expects,” “anticipates,” “intends,” “plans,” “believes,” “seeks,” “estimates,” “projects,” “forecasts,” and similar expressions. Forward-looking statements are not guarantees of future performance and involve certain known and unknown risks, uncertainties and assumptions that are difficult to predict. Actual outcomes and results may differ materially from what is expressed, forecasted or implied in the forward-looking statements. Factors that may affect the outcome of the forward-looking statements include, among other things, our ability to attract, integrate, manage and retain qualified executive search consultants; our ability to develop and maintain strong, long-term relationships with our clients; declines in the global economy and our ability to execute successfully through business cycles; the timing, speed or robustness of any future economic recovery; social or political instability in markets where we operate, the impact of foreign currency exchange rate fluctuations; unfavorable tax law changes and tax authority rulings; price competition; the ability to forecast, on a quarterly basis, variable compensation accruals that ultimately are determined based on the achievement of annual results; our ability to utilize our tax losses; the timing of the establishment or reversal of valuation allowance on deferred tax assets; the mix of profit and loss by country; our reliance on information management systems; any impairment of our goodwill and other intangible assets; and the ability to align our cost structure and headcount with net revenue. For more information on the factors that could affect the outcome of forward-looking statements, refer to our Annual Report on Form 10-K for the year

ended December 31, 2014, under Risk Factors in Item 1A and our quarterly filings with the SEC. We caution the reader that the list of factors may not be exhaustive. We undertake no obligation to update publicly any forward-looking statements, whether as a result of new information, future events or otherwise.

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Press Release Contacts:

H&S Investors & Analysts Contact:

Julie Creed - Vice President, Investor Relations & Real Estate:

1 312 496 1774, jcreed@heidrick.com

H&S Media Contact:

Lia Randazzo - Marketing Manager:

312.496.1788, lrandazzo@heidrick.com

Heidrick & Struggles International, Inc.

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