Vaughn had his breakthrough role as disabled, drunken war veteran Chester A. Gwynn in The Young Philadelphians, earning him a 1960 Oscar nomination for Best Supporting Actor.

He subsequently appeared in scores of films, notably as gunman Lee in The Magnificent Seven (1960), Walter Chalmers in Bullitt, Major Paul Krueger in The Bridge at Remagen (1969), the voice of Proteus IV in Demon Seed (1977) and Ross Webster in Superman III (1983).

(1964–68), private detective Harry Rule on The Protectors (1972–74), Morgan Wendell in the miniseries Centennial (1978–79), and Albert Stroller on the BBC Television drama Hustle (2004–12).

He won an Emmy Award for Outstanding Supporting Actor in a Drama Series for his portrayal of the White House Chief of Staff in the miniseries Washington: Behind Closed Doors.

[4] A PhD in communications, his 1970 doctoral thesis "The Influence of the House Committee on Un-American Activities on the American Theater 1938–58" is considered "the most complete and intelligent treatment of the virulent practice of blacklisting now available.

[8] His parents divorced, and Vaughn lived with his grandparents Frank and Mary Gaudel in Minneapolis while his mother traveled and performed.

[9][8][10][11] Discussing his childhood in a 1965 New York Sunday News interview, Vaughn said “I was a complete wreck as a child, emotionally unstable, excessively prideful”[12] and that he often felt miserable.

[18][17] Vaughn's original research included data from questionnaires and interviews he conducted with witnesses who had been labeled "uncooperative" by the House Un-American Activities Committee.

[5] Vaughn was inducted into the U.S. Army Reserve on November 29, 1955, and entered active duty on December 18, 1956, at Fort Ord, California.

"My job was a kind of glorified page boy position, but I was allowed to wear civvies rather than the silly uniforms often sported by studio guides and messengers in those days".

Vaughn's first credited movie role was the Western Hell's Crossroads (1957), in which he played Bob Ford, the murderer of outlaw Jesse James.

Vaughn appeared as Stan Gray in the episode "The Twisted Road" of the western syndicated series Frontier Doctor.

[22] In the film Vaughn portrayed alcoholic Chet Gwynn who lost his arm in the Korean War and was falsely accused of murder.

Vaughn recalled the morning in January when he arrived in Sturges’ office for his audition, "...an ax was hanging over every movie project in Hollywood.

Telling Vaughn he wanted to cast him based on his performance in The Young Philadelphians, Sturges said, "We don’t have a script, just Kurosawa’s picture to work from.

Senator in the film Bullitt starring Steve McQueen;[23] he was nominated for a BAFTA Award for Best Supporting Actor for this role.

This production spawned a spinoff show, large amounts of merchandising, overseas theatrical movies of re-edited episodes, and a sequel, Return of the Man from U.N.C.L.E..

[32] "I was bombarded with house and apartment keys labeled with the addresses of the adoring girls who lived behind those doors," he wrote in his 2008 memoir, A Fortunate Life.

broadcast run, Vaughn appeared as a bachelor on the premiere episode of the nighttime version of The Dating Game which aired on October 6, 1966.

Karen Carlson, the 1964 Miss America pageant first runner-up, chose Vaughn as her date, which included a trip to London, England.

[36] Vaughn first appeared on daytime television in 1995 as a guest-star playing Rick Hamlin on the CBS soap opera As the World Turns.

[2] In 2012 Vaughn appeared for three weeks in the British soap opera Coronation Street[23] as wealthy American Milton Fanshaw.

[16] In the series, Vaughn played elder-statesman American con artist Albert Stroller, a father figure to a group of younger grifters.

When show producer Simon Crawford Collins met Vaughn, he recognized "straight away that he could bring a whole new dimension to the part of Albert".

Vaughn won an Emmy for his portrayal of Frank Flaherty in Washington: Behind Closed Doors (ABC, 1977)[38] and during the 1980s starred with friend George Peppard in the final season of The A-Team.

Vaughn portrayed Presidents Franklin D. Roosevelt and Harry S. Truman,[39] in addition to Woodrow Wilson (in the 1979 television mini-series Backstairs at the White House).

In the mid-1990s, he made several cameo appearances on Late Night with Conan O'Brien as an audience member who berates the host and his guests beginning with "you people make me sick.

In 1966 they acquired the production rights to Joseph Sargent's "story idea" Bridge on the River Hudson[43] and hired Peter Allan Fields to produce a script treatment.

Vaughn said he had lived on one-quarter of his salary for the past ten years and that his business manager allowed him $25 spending money per week.

[47] In later years, Vaughn appeared in syndicated advertisements marketed by Commercial Pro, Inc. for various personal injury and workers compensation law firms, using the catchphrase, "Tell them you mean business".