Jack Griffin, the chairman and chief executive of Time Warner's magazine division, has lost his job less than six months after taking the position.
His leadership style did not fit with the company's culture, Time Warner's boss Jeff Bewkes said.
An interim management committee will run the division until a replacement is found, he added.
Time Inc publishes a number of well-known titles, including Time, People and Sports Illustrated.
"Although Jack is an extremely accomplished executive, I concluded that his leadership style and approach did not mesh with Time Inc and Time Warner," Mr Bewkes wrote in an internal memo.
Analysts said the timing of Mr Griffin's departure was unfortunate.
"It's apparent that this was a personality thing as much as a strategy thing," said Ken Doctor at Outsell research and advisory firm.
"Time Inc has a long history of stops and starts to the digital business. It's another stop to the process and its comes at a critical time."
Earlier this month, Time Warner said turnover at its magazine arm for the final three months of last year fell 4% to $1.1bn (£680m) on lower advertising and subscription sales.
The division has struggled to attract readers and advertisers as competition from online publishers has increased.