She was born Ann Steely in Siluria, Alabama. She attended Oklahoma City University and studied drama at the American Academy of Dramatic Arts before beginning her career on stage and then movies.
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 reteamed in 1950, for another movie, Side Street. Later Cathy 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.
In the 1960s, she appeared in TV shows, playing mostly small 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
In 1948 at 25 years old, she married the 48-year-old Robert Wyler, older brother of director William Wyler.
Cathy O'Donnell died of a cerebral hemorrhage brought on by cancer at the age of 46, on her 22nd wedding anniversary.
Eventide in Forest Lawn Glendale, next to her husband Robert Wyler and brother-in-law William Wyler, director of her performances in "The Best Years of Our Lives" and "Ben Hur."
The Wyler Family: Billy, William, SPACE FOR WHOM(?), Robert and Cathy.
The Best Years of Our Lives
They Live by Night
The Amazing Mr. X
The Miniver Story
The Man from Laramie
The Story of Mankind