Time Inc named Martha Nelson its editor-in-chief, making her the first woman to oversee its magazine empire, which includes Time, Sports Illustrated and People.
Nelson, whose appointment was announced by Time Inc Chief Executive Laura Lang on Tuesday, succeeds John Huey effective in January.
Huey is taking a fellowship at Harvard University's Shorenstein Center on the Press, Politics and Public Policy.
"I would venture to say that no single person at Time Inc. has built more value for the company than Martha," Lang said in a memo to staff obtained by Reuters.
"She has a broad understanding of the digital competitive landscape and knows what we need to do to succeed."
Nelson, currently Time Inc's editorial director, is the founding editor of one of its most successful titles, In Style. She has been with Time Inc for 20 years.
Nelson is taking the editorial helm at the largest U.S. magazine publisher as the industry faces unprecedented challenges including a shrinking audience and a decline in advertising revenue.
Like newspapers, magazines are trying to make a transition from print to new products for smart phones and table devices like Apple Inc's iPad.
Time Warner Inc, the parent of Time Inc, reported that revenue for its publishing assets fell 6 percent to $2.5 billion on lower advertising and subscription sales during the nine months ending September.
Newsweek, one of Time's long-time rivals, announced in October it was shuttering its print edition after nearly 80 years and going all digital.
(Reporting By Jennifer Saba in New York)