[3] Among her film roles were Tilly, the secretary of the Building and Loan, in Frank Capra's It's a Wonderful Life (1946) starring James Stewart, and the role of Pat in the drama Kitty Foyle (1940) starring Ginger Rogers.

In the 1954–1955 season, Treen appeared in 38 episodes as Emily Dodger on the CBS situation comedy Willy.

[4] Her longest-running role was as Hilda, the maid and baby nurse in 64 episodes of the NBC and CBS sitcom The Joey Bishop Show from 1962 to 1965.

[citation needed] Treen was a Republican who supported the campaign of Dwight Eisenhower during the 1952 presidential election.

[5] Treen died of cancer at her home in Newport Beach, California, on July 20, 1989, at age 82.