She was often cast in western films such as Howard Hawks's Red River (1948), and the John Ford productions She Wore a Yellow Ribbon (1949), and Wagon Master (1950).

[4] She gave a well-received performance in the dramatic film All the King's Men (1949), which went on to win the Academy Award for Best Picture, played a college graduate turned gangster's unhappy moll opposite Edmund O'Brien in the crime noir 711 Ocean Drive (1950), and co-starred with Dan Dailey in The Pride of St. Louis (1952), about major-league baseball pitcher Jerome "Dizzy" Dean.

Her film career petered out by the end of the 1950s, but she continued working frequently in television, most notably as Babs Hooten on the 1960–61 ABC sitcom, Guestward, Ho!

[citation needed] She was a staunch Republican, supporting Barry Goldwater in the 1964 United States presidential election[7] and appeared at a 1968 GOP cocktail party fundraiser for Richard Nixon.

[5] Dru died in Los Angeles, California on September 10, 1996, aged 74, from a respiratory ailment that developed from lymphedema, a result of chemotherapy she had received over her lifetime, according to her brother.