In 1940, Russell was signed to a seven-year contract by film mogul Howard Hughes and made her motion picture debut in The Outlaw (1943), a story about Billy the Kid that went to great lengths to showcase her voluptuous figure. Although the movie was completed in 1941, it was released for a limited showing two years later. There were problems with the censorship of the production code over the way her ample cleavage was displayed. When the movie was finally passed, it had a general release in 1946. During that time, she was kept busy doing publicity and became known nationally. Contrary to countless incorrect reports in the media since the release of The Outlaw, Russell did not wear the specially designed underwire bra (the first of its kind) that Howard Hughes constructed for the film. According to Jane's 1988 autobiography, she was given the bra, decided it had a mediocre fit, and wore her own bra on the film set with the straps pulled down.
Together with Lana Turner and Rita Hayworth, Russell personified the sensuously contoured sweater girl look, though her measurements of 38D-24-36 and height of 5' 7" were more statuesque than her contemporaries. Besides the thousands of quips from radio comedians, including Bob Hope, who once introducing her as "the two and only Jane Russell" and "Culture is the ability to describe Jane Russell without moving your hands", the photo of her on a haystack was a popular pin-up with servicemen during World War II. She was not in another movie until 1946, when she played Joan Kenwood in Young Widow for RKO.
In 1947, Russell attempted to launch a musical career. She sang with the Kay Kyser Orchestra on radio and recorded two singles with his band, "As Long As I Live" and "Boin-n-n-ng!" She also cut a 78 rpm album that year for Columbia Records, Let's Put Out the Lights, which included eight torch ballads and cover art that included a diaphanous gown that for once put the focus more on her legs than on her breasts. In a 2009 interview for the liner notes to another CD, Fine and Dandy, Russell denounced the Columbia album as "horrible and boring to listen to." It was reissued on CD in 2002, in a package that also included the Kyser singles and two songs she recorded for Columbia in 1949 that went unreleased at the time. In 1950, she recorded a single, "Kisses and Tears," with Frank Sinatra and The Modernaires for Columbia.