Sawyer, who was the chief operating officer at the agency, will take over from Donny Deutsch, who becomes the chairman.
Her first act in the new role was to announce the appointments of four co-presidents. Kathy DeLaney and Val DiFebo will cover the New York office, while Eric Hirschberg and Mike Sheldon will be responsible for the LA office. She is also expected to name a chief operating officer in the near future.
Deutsch said: "Linda has been critical in shaping our culture. She lives and breathes our brand."