Heidrick & Struggles International : 543772 002 bmk1

Proxy

Statement

HEIDRICK & STRUGGLES

Letter to Stockholders

April 12, 2024

Dear Fellow Stockholders,

As I begin my tenure as CEO, I am proud to be joining such an accomplished team at this exciting time in the

company's history. As a former Heidrick & Struggles client, I have a deep appreciation for the exceptional value we offer and the enormous opportunities that lie ahead.

2023 was an outstanding year for Heidrick & Struggles. We helped our clients discover and enable the visionary and transformative leadership they urgently needed during a time of almost unprecedented global and economic change. Our strong financial results reflect our success in doing that.

Even with our solid performance, I believe the opportunity in front of us is vast. The challenges facing companies today

• an AI-driven revolution in work, deepening divisions at work and in societies, and a complex geopolitical landscape, to name just a few - demand that organizations have the right leadership, armed with the right tools, to thrive and grow. We are building a company that meets this urgent need.

Three principles drive our strategy:

1. We partner with clients on some of their most important challenges, which grow in size and complexity every day. Against a backdrop of volatile operating environments and often-competingstakeholder expectations, our work powers client performance. When we effectively partner with clients to discover, enable, and advance great leaders and teams, we create substantial value for organizations and society.
2. Our platform creates unique client value. Across our business lines, we believe our platform is unrivaled in its ability to find, assess, develop, support, and promote critical talent. These businesses are built on two core foundations. First, a community of unmatched professionals who leverage unique intellectual property and advanced technology to deliver inspired work. Second, a culture that ensures we bring the best of Heidrick - across businesses and boundaries - to each client problem.
3. We are committed to transforming client value into shareholder value. For the third consecutive year, we delivered over $1 billion in net revenue. We also grew our Adjusted EBITDA to over $125 million and reported adjusted diluted earnings per share of $2.911.

Our purpose is to partner with clients to create unrivaled economic value for their organizations and communities. The evidence is very clear that great leaders, empowered with solutions to lift the performance of their teams and themselves, are the most important way to make that happen. We are hard at work creating more value for more clients in more ways - and we appreciate your partnership in this deeply rewarding work.

This year we will once again conduct our Annual Meeting in a virtual format. Stockholders attending the virtual meeting will be afforded the same rights and opportunities to participate as they would in-person.

You can attend our Annual Meeting by visiting www.virtualshareholdermeeting.com/HSII2024 where you will be able to listen to the meeting live, submit questions and vote. Information about the business to be conducted, attending the meeting and voting your shares may be found in the Notice of 2024 Annual Meeting of Stockholders and Proxy Statement.

On behalf of our Board of Directors and our entire management team, thank you for your continued confidence and investment in our firm and your warm welcome as I begin my tenure as CEO.

Sincerely,

Thomas L. Monahan III

Chief Executive Officer

1 Adjusted EBITDA and Adjusted Diluted Earnings Per Share are Non-GAAP financial measures. A reconciliation of these Non-GAAP financial measures to the most directly comparable GAAP financial measures can be found on Annexes A and B.

HEIDRICK & STRUGGLES

Proxy Statement Summary

CEO Succession

On January 23, 2024, we announced that President and CEO Krishnan Rajagopalan planned to retire after more than 23 years with the Company. Mr. Rajagopalan stepped down as President and CEO and from the Board, effective March 4, 2024, and retired as an employee the Company on April 1, 2024, after which he has continued to serve as an advisor, working closely with clients around the world. Following a planned succession process, the Board appointed Thomas L. Monahan III to succeed Mr. Rajagopalan as CEO and a member of the Board, effective March 4, 2024. The Company also appointed Tom Murray, the Company's Global Managing Partner of Executive Search, Regions, as the Company's President, reporting to Mr. Monahan, effective March 4, 2024.

A discussion of the terms of Mr. Rajagopalan's retirement is included in the Compensation Discussion and Analysis ("CD&A") under the section "CEO Succession Process," beginning on page 48. Messrs. Monahan and Murray's employment agreements and compensation packages are discussed in the CD&A under the section "Offer Letter Agreements in Connection with CEO Succession", beginning on page 68. The hiring of Mr. Monahan as CEO, as well as the promotion of Mr. Murray to President, represent the culmination of our Board's active engagement in a planned, long-term,multi-year succession process.

2023 Business Highlights

We are pleased with the financial, operational, and strategic progress achieved during fiscal 2023. The year was highlighted by our dedicated efforts to further solidify Heidrick as a leader in providing diversified solutions to our clients while advancing our strategy, with a goal to achieve a more balanced revenue profile between our search and non-search businesses, while maintaining adjusted EBITDA margin discipline. During the year, our core Executive Search business continued to deliver strong profitability; our On-Demand Talent business continued to grow; our Heidrick Consulting business improved operations and efficiencies; and we signed up our first SaaS customers for our new digital product, Heidrick Navigator, which continued to receive positive feedback from initial client usage.

Heidrick ended 2023 with:

• Consolidated net revenue of $1,026.9 million
• Record net revenue achieved in On-Demand Talent and Heidrick Consulting
• Strong balance sheet with $478.2 million in cash and cash equivalents and marketable securities
• Adjusted EBITDA was $125.6 million and Adjusted EBITDA Margin was 12.2%2

Our strong top- and bottom-line results are a testament to our ongoing efforts to further diversify our business, as we continue to make investments for the long-term in digital product innovation and aim to set the stage for prolonged, profitable growth.

2 Adjusted EBITDA and Adjusted EBITDA Margin are Non-GAAP financial measures. A reconciliation of these Non-GAAP financial measures to the most directly comparable GAAP financial measures can be found on Annexes A and B.

PROXY STATEMENT 2024

2023 Environmental, Social and Corporate Governance Highlights

Heidrick accomplished many of its ESG objectives in 2023. We published our third ESG report which covered activities that took place during the fiscal year 2022. The ESG report outlines how we address our environmental and social impact, our governance structures and how we integrate ESG considerations across our business lines. Highlights from

2023 included:

• We completed a comprehensive assessment to determine our key ESG priorities that are important to our internal and external stakeholders.
• We committed to submitting an emissions reduction target through the Science Based Targets initiative (SBTi) in 2024. This will be a collaborative effort, and we will work across business lines, geographies and functions to develop targets and implementation plans that will allow us to reduce our carbon emissions, while maintaining our client focus.
• We established an ESG governance framework by forming the ESG Working Group and ESG Executive Steering Committee. These groups provide oversight of our ESG strategies and initiatives by providing cross-functional perspectives, setting direction and helping define priorities with the goal of creating alignment and building support for our ESG efforts throughout the business.
• We are proud to share our progress advancing diversity, equity and inclusion across our business to foster
  representation at all levels and functions of the firm. As a premier provider of leadership advisory services, our culture helps us attract, develop and retain the highest-performing talent and build a more diverse and inclusive firm.

People highlights from 2023 include3:

• 38% of our own Board members were women, and 25% were racially/ethnically diverse.
• Women represented 63% of our overall workforce, 66% of our new hires4 and 64% of our promotions globally for the year.
• People of color represented 27% of our U.S. workforce, 30% of our new hires5 and 20% of our promotions for the year.
• In 2023, our Learning & Development team delivered over 10,500 hours of facilitated training to our colleagues globally, and employees completed over 5,000 self-paced courses.

As we continue to make strides internally to advance our efforts in ESG matters, we also provide talent and human capital solutions that support our clients on their ESG journeys. Key 2023 updates include6:

• At the Board of Directors level, 61% of our U.S. placements and 58% of our global placements7 were diverse, an
  outcome of our Board Diversity Pledge, a global commitment that a minimum of half of the initial board candidates presented by us to our clients globally on an annual basis will be diverse.
• Across practices, 42% of our total U.S. placements were diverse.
• We completed 300+ ESG related search and consulting engagements for clients, as further described below.

2023 Compensation Highlights

• Heidrick's compensation program is guided by a pay-for-performance philosophy. A significant portion of executive compensation is based on variable pay, which aligns pay with performance.
• Our program is designed to drive long-term stockholder value by aligning our business strategies and operating priorities with stockholders' interest and rewarding executives for top- and bottom-line growth.
• Our compensation philosophy focuses on attracting, retaining and motivating leaders that have the right skills to support the Company's culture and drive short-term and long-term success.

1. As of December 31, 2023.
2. Excludes temporary employees deployed to clients in our On-Demand Talent business.
3. Excludes temporary employees deployed to clients in our On-Demand Talent business.
4. As of December 31, 2023.
5. Global updates comprise females globally plus ethnic diversity for males in the United States, Canada, Australia and the United Kingdom ("UK") (the countries where we currently track ethnicity). For the UK, data relating to ethnic diversity is classed as "sensitive personal data" and requires self-identification. Therefore, for the placement statics relating to total or ethnic diversity (i.e.: include data from the UK) is not necessarily reflective of our placements but of those placements that have self-identified..

4 PROXY SUMMARY

HEIDRICK & STRUGGLES

2023 Compensation Best Practices

Our compensation policies and practices include:

Independent HRCC. All of the members of the HRCC are independent.

Independent Compensation Consultant. The HRCC receives objective advice from an independent

compensation consultant.

Emphasis on Variable Pay. At least 65% of total target executive compensation is delivered through variable pay tied to the achievement of certain Company and individual performance goals.

Annual Assessment. The HRCC conducts an annual assessment of compensation policies to ensure that they are aligned with the Company's performance objectives, are competitive in the executive search and leadership consulting industry, and do not encourage undue risk.

Annual Payout Limits. The potential annual payout on annual incentive plan and PSUs is limited to 200% of target, as further described on pages 57 and 63.

Long-TermVesting. We encourage retention and long-term value creation by providing a combination of time- and performance-based equity awards that vest over three years.

No Excise Tax Gross-Ups. We do not provide excise tax gross-ups to the executive officers.

Double-TriggerVesting. Our equity awards are subject to double-trigger vesting under our Change in

Control Severance Policy.

Clawback Policies. We maintain two robust clawback policies that cover, including a standalone clawback policy in compliance with the Dodd-Frank requirements as well as a misconduct policy, all incentive-based

compensation.

Stock Ownership Guidelines. The CEO is required to own five times their annual base salary in Company common stock, and all other NEOs are required to own two times their annual base salary. The CEO or other NEOs must retain ownership of Company shares in an amount equal to 50% of the net after-tax value of any newly-vested RSUs, performance shares and/or PSUs until the applicable multiple requirement is met, as further described on page 65.

No Hedging or Pledging. We do not permit our executives to hedge or pledge Heidrick stock.