Collier's acting career started in 1938, when she had a small but credited role in A Desperate Adventure, starring Ramon Novarro and Marian Marsh. From 1940 through 1949, her career would be active and somewhat successful, with her playing mostly heroine roles in B-movies. During that period, she often starred opposite western stars Bob Steele, Tom Tyler, and Dennis Moore. In 1950, she starred in the sci-fi serial The Flying Disc Man from Mars.

Collier was sometimes called the Fourth Mesquiteer because seven of Republic Pictures' The Three Mesquiteers movies featured her as the female lead. Collier played Carol in the soap opera Dear John, which ran on CBS in the 1930s and 1940s. Beginning December 6, 1948, she was featured in You, a program on KMGM in Los Angeles, California.