
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.
In 1949, Collier co-starred in City Desk, a drama about activity in the newsroom of a newspaper. From 1950 through 1957, she starred mostly on television series episodes. She played Mary, the hero's girlfriend and sidekick, in 58 episodes of the television series Boston Blackie, which ran from 1951 to 1954. She retired from acting after 1957.

Ladies Courageous
1944 · as Jill Romilly

A Night in Casablanca
1946 · as Annette

Jungle Woman
1944 · as Joan Fletcher

Slave Girl
1947 · as Aleta

The Naughty Nineties
1945 · as Miss Caroline Jackson

Follow the Boys
1944 · as Lois Collier (uncredited)

Weird Woman
1944 · as Margaret Mercer

Cobra Woman
1944 · as Veeda

The Affairs of Jimmy Valentine
1942 · as Receptionist

Young Ideas
1943 · as Co-ed (uncredited)

Girl on the Spot
1946 · as Kathy Lorenz

Prices Unlimited
1944

Miss Mink of 1949
1949 · as Alice Forrester

The Crimson Canary
1945 · as Jean Walker

Jungle Queen
1945 · as Pamela Courtney

The Man Who Returned to Life
1942 · as Mary Tuller

The Cat Creeps
1946 · as Gay Elliot

Santa Fe Scouts
1943 · as Claire Robbins