Executive search firm Heidrick & Struggles International Inc. (NASD: HSII) appointed acting CEO Krishnan Rajagopalan as president and CEO.

Rajagopalan, formerly the firm’s executive VP and managing partner – executive search, stepped in to serve as acting CEO and interim principal executive officer in April, when CEO Tracy Wolstencroft took a three-month leave of absence for treatment of a benign lung condition. Wolstencroft will now assume the role of chairman of the board, succeeding Richard “Dick” Beattie, who remains on the board as lead independent director.

The company said Wolstencroft is responding well to his treatment regimen, but more time is required for a complete recovery. Given the projected timing, the board believes the firm will be best served by Wolstencroft assuming the role of chairman and Rajagopalan succeeding him as president and CEO.

Wolstencroft joined Heidrick & Struggles as president and CEO in 2014, following a 25-year career at Goldman, Sachs & Co.

Rajagopalan joined Heidrick in 2001 in executive search and served as head of global practices beginning in April 2014. He was appointed an executive VP in January 2015. Rajagopalan held other leadership roles including global practice managing partner, technology and services, from 2010 to 2014 and global practice managing partner, business/professional services from 2007 to 2010.

“We are thankful that Tracy’s recovery is progressing well,” Beattie said. “While we are disappointed that he will not return as our CEO, we understand and respect his decision. Tracy is an extraordinarily talented executive and a terrific person. He has led Heidrick exceptionally well for more than three years. We will continue to benefit from his strategic leadership and market expertise as chairman of the board.”