She became influential in a male-dominated world and a close confidante of Post publisher Katharine Graham. She was awarded journalism's highest honor, a Pulitzer Prize for Editorial Writing, in 1978 and spent 20 years as the editorial page editor for the Washington Post and 25 years as a columnist for Newsweek.
She never married, something she came to regret. When diagnosed with cancer, Greenfield partly retired to Bainbridge Island in her native Washington, where she wrote a posthumously published memoir entitled Washington. She died of the disease, aged 68.