James Coburn, the actor who died on Monday aged 74, never quite ranked in the top flight of Hollywood stars, yet his powerful performances in several classic films, such as The Magnificent Seven , The Great Escape and Pat Garrett and Billy the Kid rightfully ensured his status as a minor screen legend; but it was only in 1998, after many years confined to supporting roles or leads in films of little distinction, that he won an Oscar for his performance as a drunken abusive father in Paul Schrader's adaptation of the Russell Banks novel, Affliction .

Coburn typified the Hollywood star of the post-studio era. With actors no longer groomed for stardom under seven-year contracts, they had to make their mark on their own initiative. Conveyor-belt good looks, as exemplified by Robert Taylor and Tyrone Power, no longer sufficed. This was the making of more rugged, weather-beaten actors such as Coburn and Lee Marvin, whose unconventional appearance stood out from the crowd.

Coburn's features were anti-heroic; he had a mouthful of teeth and a jaw set permanently at an angle to the rest of him. It was said that even in repose he looked as if he was about to spit. He was initially typecast as a "heavy", but as times and expectations changed, he was able to gravitate to more sympathetic roles, and even to comedy.

Coburn's deep baritone voice, languorous physicality and toothy grin first came to the attention of international audiences when he played Britt, one of the mercenaries hired to protect a Mexican village in The Magnificent Seven (1960), a remake of Akira Kurosawa's Japanese epic, Seven Samurai , transposed to the Wild West. Starring alongside Steve McQueen, Charles Bronson and Robert Vaughn, Coburn played a knife-expert, who could throw his blade faster than any man could draw his gun.

But it was only towards the end of his life that Coburn achieved the recognition he deserved when he won the Best Supporting Actor Oscar for his performance in Affliction . He played the vile and manipulative "Pop" Whitehouse, who passes a legacy of alcoholism and violence on to his son, played by Nick Nolte.

For this role he thinned his hair, wore padding and raised his voice a register, jettisoning everything that defined the James Coburn "cool" and revealing what a great actor he could be. At the Academy Awards ceremony, the cheers were long and loud for the veteran whose work had finally been acknowledged.

But as befitted a tough guy, he broke a presentation rule - in force since Greer Garson's 1942 acceptance speech ran over an hour - that no winner should speak for more than three minutes. As Coburn's speech breached that limit, the orchestra cut in to shut him up. Undeterred, he shifted to his back-of-the-auditorium voice and shut them up instead, telling the audience, "some of them you do for money, some of them you do for love. This is a love child."

James Coburn was born on August 31 1928 at Laurel, Nebraska, the son of a car mechanic, whose family lost an extensive cattle empire in the Depression. When James was five, the family moved to Compton, California. There he was educated at the local junior college, after which he joined the Army, wangling a job in PR, then as a disc jockey on an army-sponsored Texas radio station. He was bitten by the movie-bug when he was posted to Mainz, in Germany, to narrate army films.

Discharged from the services, he enrolled at the Los Angeles City College drama department during which period he appeared in several college productions and a staging of Billy Budd at the La Jolla Playhouse with Vincent Price.

Encouraged, Coburn drove, in 1954, to New York, where he began to attract work in TV advertisements and live television plays. Eventually he reached Hollywood, where he first won assignments in Westerns and on the General Electric Theater programme, hosted by Ronald Reagan.

Contrary to his image of the gruff, laconic "natural", Coburn was committed to the necessity of training in mastering the art of acting. "Acting," he explained, "is not just an accident. It has to become a conscious, artistic effort that you're in control of." Even his trademark gravelly voice was worked on. "I had to build in a whole upper register, so that it kind of sang and rang a little bit."

Following appearances in the TV Western series Bonanza , Gunsmoke and Wanted: Dead or Alive , Coburn's first film role was in Budd Boetticher's Western Ride Lonesome (1959) as a villain. Other supporting parts in Westerns followed, until in 1960 he was picked for The Magnificent Seven .

On the strength of their performance together in The Magnificent Seven , Coburn and McQueen were teamed for the war films Hell is for Heroes (1962) and The Great Escape (1963). The latter, based on the true story of a mass breakout from a Nazi prison-camp by Allied PoWs, has remained a perennial TV attraction and, having worked together so often, McQueen and Coburn became friends. "We would always hang out together," Coburn later recalled, "smoke grass, get high and go up to the mountains and drive fast cars."

Unlike McQueen, however, Coburn looked destined for a second-string career playing outlaws and hoods, such as the one who menaces Audrey Hepburn and Cary Grant in Charade (1963). But after fine work as a bearded Indian scout in Sam Peckinpah's Major Dundee and as a pirate in A High Wind in Jamaica (both 1965), he achieved star billing with Our Man Flint (1966).

The first of many 007 spoofs, it starred Coburn as a superspy with a cigarette lighter with 82 different espionage uses and innumerable nymphets to light it. Coburn hated the role but agreed to a sequel, In Like Flint (1967), which made his name.

In the late 1960s, Coburn set up his own production company, but his first self-produced film, The President's Analyst (1967) pleased only the critics. A biting satire on Cold War conspiracy theory films in which the ultimate villain turns out to be the telephone company, its message was lost on the public.

However, A Fistful of Dynamite (1971 - also known as Duck You Sucker!), the spaghetti Western he made in Italy for Sergio Leone, in which Coburn played a munitions expert attached to Mexican revolutionaries, turned out to be a worldwide success.

The best film Coburn made in these years was Pat Garrett and Billy the Kid (1973). Directed by Sam Peckinpah, Coburn played the gunman-turned-sheriff Pat Garrett in the tragic drama of how Pat and Billy, former colleagues, are driven to a final shoot-out that neither wants.

The film suffered mindless re-editing at the time, but after Peckinpah's death, it was restored almost to its original state, with Coburn's Garrett and Kris Kristofferson's outlaw closing in on the final encounter.

Through the late 1970s and early 1980s, Coburn made many indifferent movies, ranging from The Carey Treatment (1972) to The Baltimore Bullet (1990) and Looker (1981), a Michael Crichton thriller in which Albert Finney investigates Coburn's medical scam.

A rare exception to the general decline was Cross of Iron (1977), Peckinpah's characteristically bleak and violent tale of a retreating and broken German army unit at the end of the Second World War. Coburn regained his form as a disillusioned Wehrmacht corporal facing defeat at the hands of the advancing Soviet Army.

By the mid-1980s, as his popularity as an actor was waning, he was struck down by rheumatoid arthritis. For two years he was unable to walk at all, and for more than a decade he was in constant pain. He attributed his affliction to "not letting the negative emotion out" after his divorce, and when conventional medicine failed to help he turned to alternative remedies, eventually finding a homeopathic drug which proved effective.

Coburn's new found vigour enabled him to return more fully to the screen and he played a number of parts which capitalised on his past glories, such as the old-time rancher in Young Guns II (1990) and the suave secret agent in the feeble Hudson Hawk (1991).

With his role in Affliction , however, Coburn finally got the chance to prove himself, after bigger stars such as Paul Newman shied away from playing the contemptible "Pop" Whitehouse. He was unconcerned as to the effect playing such a character might have on his career. "That's why we're actors," he explained, "because we want to discover other aspects of ourselves . . . I'm not that way at all in real life, but to discover that, that it's within all of us, and to find it in myself, was so exciting."

James Coburn married first, Beverly Kelly, whom he divorced in 1979. In 1993 he married Paula Murad, a television newsreader, who survives him with a son and a stepdaughter from his first marriage.