Powers Boothe, seen in 2012, died May 14. He won an Emmy Award in 1980 for playing cult leader Jim Jones in the TV drama “Guyana Tragedy.” (Fred Prouser/Reuters)

Powers Boothe, a tall, gravelly voiced character actor who received an Emmy Award in 1980 for playing cult leader Jim Jones in the TV drama “Guyana Tragedy” and went on to play sinister roles in TV’s “Deadwood” and in movies such as “Tombstone,” “Sin City” and “The Avengers,” died May 14 at his home in Los Angeles. He was 68.

Mr. Boothe’s publicist confirmed the death but did not disclose the cause.

After “Guyana Tragedy,” Mr. Boothe portrayed other memorable antagonists, including ruthless saloon owner Cy Tolliver in “Deadwood,” the gunman Curly Bill Brocius in “Tombstone” (1993) and a corrupt senator in “Sin City” (2005) and the sequel “Sin City: A Dame to Kill For” (2014). He played Gen. Alexander M. Haig Jr., the White House chief of staff, in director Oliver Stone’s “Nixon” (1995) and a sheriff in Stone’s “U Turn” (1997).

On TV, he was also the power-hungry Vice President (and later President) Noah Daniels on Fox’s “24.” More recently, he appeared as industrialist Gideon Malick in the film “The Avengers” (2012) and on ABC’s “Marvel’s Agents of S.H.I.E.L.D.” and was a businessman and political kingmaker on the ABC drama “Nashville.”

The well-received 1985 John Boorman film “Emerald Forest,” based on a true story, provided Mr. Boothe one of his rare outings as a protagonist. He played an American engineer who was in South America to oversee the construction of a hydroelectric dam and whose son is kidnapped in the Amazon. New York Times film critic Janet Maslin said Mr. Boothe “makes a hero of [his character] without losing track of the man’s limitations.”

Powers Allen Boothe was born to a farming family in the west Texas town of Snyder on June 1, 1948. He attended Southern Methodist University and later did theater work with repertory groups before making his way to New York’s theater scene.

He told the Associated Press in 1981 that he made ends meet at first by working in a Broadway restaurant, and his family was always ready to welcome him back.

“They kept telling me, ‘Come home and we’ll have a place for you on the farm,’ ” he said.

He eventually found roles and appeared on Broadway in 1979, as a cowboy in James McLure’s well-received but short-lived one-act comedy “Lone Star.” On-screen, he had small parts as an actor in “The Goodbye Girl” (1977), as a salesman in the Al Pacino police drama “Cruising” (1980) and as a military officer in “Red Dawn” (1984).

He fared better on television. In addition to portraying Jim Jones, he played the title character in “Philip Marlowe, Private Eye” (1983), an HBO drama series based on Raymond Chandler’s hard-bitten detective.

Besides his wife, the former Pam Cole, survivors include two children. A complete list of survivors was not immediately available.

Mr. Boothe told the Los Angeles Times in 2007 that he relished his reputation as a go-to guy for menacing roles.

“There’s something about playing the baddies that people like,” he said. “They’re more fun and people tend to remember them, particularly if you do them well.”