Sister of Charles B. Fitzsimons, Margot Fitzsimons, James O'Hara, Clare Hamilton and Peggy FitzSimons.
Starred with John Wayne in 5 movies: Rio Grande (1950), The Quiet Man (1952), The Wings of Eagles (1957), McLintock! (1963) and Big Jake (1971). The first three were directed by John Ford.
Was John Wayne's favorite actress and he considered her a real friend, the only woman he thought of in that way. When he lay dying in his hospital bed, he watched on television as Maureen petitioned Congress to give him a Congressional Gold Medal, which they did by a unanimous vote.
Was originally cast as Isabel Bradley in The Razor's Edge (1946) but was taken off by Darryl F. Zanuck she was replaced by Gene Tierney, Zanuck would soon cast her in the classic Miracle on 34th Street (1947).