Cathy O'Donnell was born Ann Steely in Siluria in Shelby County in central Alabama. She attended Oklahoma City University and studied drama at the American Academy of Dramatic Arts before beginning her career on stage, followed by motion pictures.

Career 

In 1945 while under contract with Samuel Goldwyn, she made her debut in an uncredited role as a nightclub extra in Wonder Man. The next year she had her first major role in The Best Years of Our Lives, playing Wilma Cameron, the high-school sweetheart of double amputee Homer Parrish, played by real-life World War II veteran/amputee Harold Russell.

She was loaned out to RKO for one of her most memorable films, They Live by Night starring with Farley Granger. The two actors later re-teamed in 1950, for another movie, Side Street. Later O'Donnell starred in The Miniver Story, as Judy Miniver and also had a supporting role in Detective Story. She appeared as Barbara Waggoman, the love interest of James Stewart's character in the western The Man from Laramie. Her final film role was in Ben-Hur, where she played the title character's sister, Tirzah. In the 1960s, she appeared in TV shows, playing mostly bit parts on shows such as Perry Mason, The Rebel and Man Without a Gun. Her last screen appearance was in 1964, in an episode of Bonanza.

Personal life and death 

On April 11, 1948 at 24 years old, she married the 48-year-old Robert Wyler, the elder brother of famed film director William Wyler. At the age of 46, O'Donnell died of a cancer-related cerebral hemorrhage, on the date of her 22nd wedding anniversary.

Source: Wikipedia