She was the longest-serving First Lady of the United States , holding the post from March 1933 to April 1945 during her husband President Franklin D. Roosevelt 's four terms in office .
Anna Eleanor Roosevelt ( October 11 , 1884 − November 7 , 1962 ) was the longest-serving First Lady of the United States , holding the post from 1933 to 1945 during her husband President Franklin D. Roosevelt 's four terms in office .