In 1946, she played the title role in My Darling Clementine and Clifton Webb's unfaithful wife in The Dark Corner.

Following the success of My Darling Clementine, Downs was cast in a prison drama For You I Die (1947), an Abbott and Costello comedy The Noose Hangs High, and several Western films.

In 1949, she participated in a later famous Life magazine photo layout, in which she posed with other up-and-coming actresses, Marilyn Monroe, Lois Maxwell, Suzanne Dalbert, Laurette Luez, Jane Nigh, and Enrica Soma.

[6] In 1959, she portrayed "Amelia Roberts" in the episode "Marked Deck" (S1E21) of the western TV series Bat Masterson.

Downs worked sporadically on TV during the 1960s, with her final appearance in 1965 on Perry Mason as murder victim and title character Millicent Barton in "The Case of the Hasty Honeymooner".