John Martin Jr. joined Comscore Inc.'s board as chairman of the finance committee, effective May 22.
Martin recently was chairman and CEO of Turner Broadcasting System Inc. where he oversaw cable networks such as CNN (US) and TBS (US).
Martin replaced Rob Norman, who stepped down from the company's board and will transition to a strategic consultant role, the company said May 23.
The media measurement company has seen recent shake-ups among its top brass and also recently implemented a plan to reduce its workforce.
"Throughout my career, I have led companies through transition, formulated and achieved their strategies, and generated superior shareholder returns," said Martin in a statement. "I look forward to working with the Comscore Board and management to achieve this goal."