Rosemary was born in Indianola, Iowa in 1913, to dentist Lorenzo Mullican and his wife, Cora Bell Hicks.^[3] She had four sisters (Leotabel (Leota), Dorothy (Lola), Martha and Priscilla, three of whom later had careers in entertainment. As children, Rosemary and her sister Priscilla traveled to Des Moines every weekend to study dancing with Rose Lorenz, a renowned dance teacher.^[4] The girls made their first professional appearance on September 30, 1930, at Des Moines' Paramount Theater. In 1930, Rosemary performed on stage as part of the entertainment accompanying the release of her sister Lola's Hollywood movie Good News. Rosemary, a member of the National Honor Society, graduated from Indianola High in 1931 and attended Simpson College for a while, playing on the freshman basketball team.^[4]

In 1932 Rosemary moved with her mother to New York, where her older sisters Leota and Lola had already made their debuts on Broadway. Fred Waring, an orchestra leader, heard Rosemary and Priscilla singing, and contracted the Lane sisters to join his band, The Pennsylvanians.^[5]

Rosemary and Priscilla remained with Fred Waring for almost five years. In 1937, Waring was engaged by Warner Bros. in Hollywood to appear with his entire band in Varsity Show, a musical starring Dick Powell. Both Rosemary and Priscilla took feature roles in the film.^[6][7] Lane's next film was the musical Hollywood Hotel, in which she co-starred with sister Lola, and Powell, before starring in Gold Diggers in Paris, opposite Rudy Vallee.

Priscilla, Rosemary, and Lola appeared as three of four sisters (the fourth being Gale Page) in Four Daughters in 1938; in the similarly themed Daughters Courageous in 1939, and in two sequels, Four Wives in 1939 and Four Mothers in 1941. She also starred in The Oklahoma Kid in 1939, playing a 'real girl of the West' who falls in love with James Cagney, while Humphrey Bogart plays the 'real villain'.^[8]

Lane earned good reviews for The Boys from Syracuse in 1940, based on Rodgers and Hart's Broadway hit of 1938. The next year she made an unusual move for a film actress of her era by becoming a Broadway star in the musical Best Foot Forward, as Gale Joy, which opened on Broadway at the Ethel Barrymore Theatre on October 1, 1941. It closed after 326 performances on the Fourth of July 1942.^[9][10] Lane closed out her film career in 1945 with Sing Me a Song of Texas, as nightclub singer Laurie Lang, the niece of a wealthy Texas rancher. She began a career selling real estate from an office in Pacific Palisades.

In 1942, a street in Burbank, California was named Rosemary Lane in her honour.^[11]

Lane married Hollywood makeup artist George H. "Bud" Westmore on December 28, 1941.^[12] They were married for 13 years and had a daughter, Bridget Westmore.^[13] The couple divorced in 1954.^[14]

Lane died of diabetes and pulmonary obstruction at Motion Picture Country Hospital on November 25, 1974, in Woodland Hills, California at the age of 61.^[13] She was buried in an unmarked grave at Forest Lawn Memorial Park in Glendale, California with a grave marker finally placed in 2012.^[15]

• Rosemary Lane at IMDb
• Rosemary Lane at Find a Grave