Hull was born January 3, 1877, in Newtonville, Massachusetts, one of four children born to william H. Sherwood and Mary Elizabeth ("Minnie") Tewkesbury, but would later shave years off her true age. She attended the New England Conservatory of Music and Radcliffe College, both in the Boston area.
Hull made her stage debut in stock in 1905, and after some years as a chorus girl and touring stock player, she married actor Shelley Hull (the elder brother of actor Henry Hull) in 1910. After her husband's death as a young man, the Actress retired until 1923, when she returned to acting using her married name, Josephine Hull. The couple had no children.
She had her first major stage success in George Kelly's Pulitzer-winning Craig's Wife in 1926. Kelly wrote a role especially for her in his next play, Daisy Mayme, which also was staged in 1926. She continued working in New York theater throughout the 1920s. In the 1930s and 1940s, Hull appeared in three Broadway hits, as a batty matriarch in You Can't Take It with You (1936), as a homicidal old lady in Arsenic and Old Lace (1941), and in Harvey (1944). The plays all had long runs, and took up ten years of Hull's career. Her last Broadway play, The Solid Gold Cadillac (1954–55), was later into a film version with the much younger Judy Holliday in the role.
Hull made only six films, beginning in 1927 with a small part in the Clara Bow feature Get Your Man, followed by The Bishop's Candlesticks in 1929. That was followed by two 1932 Fox features, After Tomorrow (recreating her stage role) and The Careless Lady.
She missed out on recreating her You Can't Take It With You role in 1938, as she was still onstage with the show. Instead, Spring Byington appeared in the film version. Hull played Aunt Abby who, along with Jean Adair as Aunt Martha, was one of the two Brewster sisters in the film version of Arsenic and Old Lace (1944) starring Cary Grant and Priscilla Lane, and Hull appeared in the screen version of Harvey (1950), for which she won the Academy Award for Best Supporting Actress. Variety credited Hull's performance: "the slightly balmy aunt who wants to have Elwood committed, is immense, socking the comedy for every bit of its worth".
After, Hull made only one more film, The Lady from Texas (1951); she had also appeared in the CBS-TV version of Arsenic and Old Lace in 1949, with Ruth McDevitt, an Actress who often succeeded Hull in her Broadway roles, as her sister.
Josephine Hull died on March 12, 1957, aged 80, from a cerebral hemorrhage.
