Time Inc, publisher of Sports Illustrated, People and Time magazines, appointed Rich Battista as its chief executive, succeeding Joe Ripp.
The company said on Tuesday that Ripp, Time Inc's CEO since 2013, will continue as its executive chairman.
Ripp was chief financial officer in an earlier stint at Time Inc, which was spun off from Time Warner Inc.
Ripp, 64, had a health scare a couple of weeks ago and stents put in to open clogged heart arteries, and decided to step down shortly after, according to two people familiar with the situation who wished to remain anonymous because the matter is private.
"Joe came back to Time Inc to steady the ship, but never planned to stay forever," a Time Inc spokeswoman said.
"He feels that now is the right time to pass the baton. The company's foundation is strong and it's the right time for Rich to take over as CEO," the spokeswoman said in an emailed statement.
Battista, who joined Time Inc last year, has been its executive vice president.
The shuffle comes nearly a month after activist investor Jana Partners revealed a 5 percent stake in the company.
Time has already held one meeting with Jana regarding the average age of the board members, according to the New York Post. (nyp.st/2cEYGmn)
Shares of Time Inc were marginally lower in early trading on Tuesday.
(Reporting by Narottam Medhora in Bengaluru and Jessica Toonkel in New York; Editing by Maju Samuel)