Cathy O'Donnell, born Ann Steely, was an American actress active primarily during the 1940s and 1950s. Discovered by producer Samuel Goldwyn, she achieved immediate recognition for her debut role in William Wyler's masterpiece *The Best Years of Our Lives* (1946), which won the Academy Award for Best Picture. Her career is significantly associated with the film noir genre, especially for her memorable performance in Nicholas Ray's film *They Live by Night* (1948), alongside Farley Granger. Her other notable works include *Detective Story* (1951), also directed by Wyler, the western *The Man from Laramie* (1955), and the epic *Ben-Hur* (1959), in which she played Tirzah, the protagonist's sister. Although she did not receive any major individual awards, her contribution to critically acclaimed films secured her a prominent place in the history of classic Hollywood cinema, before her premature retirement from acting and her death.