His first screen role as the mute Boo Radley in To Kill a Mockingbird (1962) left a lasting impression, and his visibility grew in such films as The Chase, Bullitt, True Grit, The Rain People and MASH. Duvall received his first Oscar nomination for The Godfather (1972); he scored another nomination for Apocalypse Now and a third for The Great Santini.
He finally earned a Best Actor Oscar for playing country singer Mac Sledge in Tender Mercies (1983) and was also nominated for The Apostle (which he also directed) and A Civil Action. Duvall has excelled in cowboy roles that have led to Emmy and Golden Globe recognition, including the miniseries Lonesome Dove (1989) and Broken Trail (2006), for which he won his first Emmy for Best Actor in a Miniseries.