Born Harriette Arlene Lake in Valley City, North Dakota, Sothern left home very young and began her film career as an extra in silent films in 1927, aged 18.

During 1929 and 1930, she appeared as a chorus girl in such films as The Show of Shows and Whoopee! (as one of the "Goldwyn Girls").

In 1934 she signed a contract with Columbia Pictures but after two years the studio released her from this contract, and she was signed by RKO Pictures in 1936.

After a string of films that failed to attract an audience, Sothern left RKO and was signed to MGM, making her first film for them in 1939.

In a role originally intended for Jean Harlow, Sothern was cast as "Maisie", a bold, brassy but somewhat scatter-brained showgirl who was also an amateur detective.

After years of trying, Sothern had her first real success, and a string of "Maisie" film sequels and radio plays took her through to the late forties.

She appeared in A Letter to Three Wives in (1949) and the film earned her excellent reviews, but did not stimulate her career.

By the fifties she was rarely seen in films and was appearing regularly in television. She was the lead in the series Private Secretary from 1953 until 1957, and The Ann Sothern Show from 1958 until 1959. Both programs were very successful and earned Sothern four Emmy Award nominations, but a bout of hepatitis had left her with a bloated and overweight appearance, and she preferred not to be seen.

In 1965 she was heard as the voice of Mom in the bizarrely campy, universally derided, and worst of all, unsuccessful series My Mother The Car, which co-starred Jerry Van Dyke.

During this period, Sothern made occasional guest appearances on The Lucy Show with her old MGM cohort, Lucille Ball. In 1967 her old boss, Desi Arnaz, approached her to co-star with Eve Arden as battling neighbors in The Mothers-In-Law but NBC felt that Sothern's style was too similar to Arden's. The very differently styled and quite younger Kaye Ballard got the part.

She resumed working sporadically on television until the mid 1980s, including a television remake of her earlier success A Letter To Three Wives. Her final film role was in The Whales of August in 1987.

Her role as the neighbour of elderly sisters, played by Lillian Gish and Bette Davis, with romantic interest provided by Vincent Price, brought Sothern her first and only Best Supporting Actress Academy Award nomination after 60 years in the business. However, she lost to Olympia Dukakis.

She had been married to actor, Robert Sterling, and had a daughter, actress Tisha Sterling.

She retired from acting, and died at her home in Ketchum, Idaho from heart failure, aged 92.

She has two stars on the Hollywood Walk of Fame - for Motion Pictures at 1612 Vine Street, and for Television at 1634 Vine Street.