Hopkins studied under Uta Hagen and at the Desilu Playhouse, where his work netted him an agent and an audition for director Sam Peckinpah. Soon thereafter he made his film debut in Peckinpah's violent, strikingly elegiac landmark Western, "The Wild Bunch" (1969). With his tousled hair, clear eyes and Southern drawl, Hopkins adeptly played a variety of yokels, wily and stupid alike, who could be sensitive and sympathetic. More often, though, he did a delicious job of unsettling viewers with his potent squint as deceptive villains or as blatantly reckless types, given to macho posturing and its attendant mayhem.
The tough, laconic Hopkins was well-suited to action fare, from the war epic "The Bridge at Remagen" (1969) to the TV-movie "The Kansas City Massacre" (1975), in which he played gangster "Pretty Boy" Floyd, to crime dramas including Peckinpah's "The Getaway" (1972), "White Lightning" (1973), "Midnight Express" (1978) and the direct-to-video "President's Target" (1993). His rugged stance has made him especially at home in the Westerns which have kept him busy, from "Monte Walsh" (1970), "The Man Who Loved Cat Dancing" (1973) and "Posse" (1975) through TV-movies like "The Last Ride of the Dalton Gang" (1979) and "Louis L'Amour's 'Down the Long Hills'" (1986). He was fine in the feature "The Ballad of Little Jo" (1993), as the rancher who gives the sexually disguised heroine a chance at sheep herding. Hopkins' iconic value in Westerns was even used reflexively in "The Day of the Locust" (1975), an adaptation of Nathanael West's classic novel about Hollywood, with Hopkins as a troubled cowboy stuntman.
Although Hopkins gave a fine performance in his first feature lead, the intriguing if minor road picture "The Only Way Home" (1972), he never quite caught on as a leading man. He has kept busy, though, if sometimes in rather minor credits. His roles as aggressive outsiders have gradually been replaced by lawmen and other similar roles: In three features made almost back to back, "Trapper County War", "The Bounty Hunter" (both 1989) and "The Final Alliance" (1990) he played sheriffs. Hopkins has also tried TV series, including a stint as the bush pilot who aids the woodsy "Doc Elliot" (1973-74), and one season as Matthew Blaisdel, the geologist enamored of Krystle (Linda Evans), on the primetime soap, "Dynasty" (1981). Hopkins occasionally reprised the role during the show's long run, briefly terrorizing the entire cast during the 1987-88 season.