Lorenzo Semple Jr. was one of the hottest screenwriters in Hollywood in the 1970s and ’80s, working on star-studded films such as “Papillon,” with Steve McQueen and Dustin Hoffman; “Three Days of the Condor,” headlined by Robert Redford; and “Never Say Never Again,” Sean Connery’s last movie as James Bond.

But, rare in the trade, Mr. Semple didn’t much mind if he was not the sole writer on a film.

“Almost all the good scripts I’ve been involved in, I’ve been fired off of for one reason or another,” he said in a 2011 video interview conducted by the Writers Guild Foundation.

One of his favorite projects came before any of the blockbuster movies. He was the first writer and executive story editor on the wacky, irreverent and successful “Batman” TV series that made its debut in 1966 and starred Adam West.

“I think ‘Batman’ in general was much the best thing I ever wrote,” Mr. Semple said of the show, which was done without a lot of oversight by executives.

Mr. Semple died March 28 at his home in Brentwood, Calif., a day after his 91st birthday, said his wife, Joyce. No cause was reported.

After not being active in the movie business for a couple of decades, he experienced a new surge of popularity in 2007 in front of the camera on “Reel Geezers,” a series of online shows he did with veteran agent Marcia Nasatir in which they would review current films and bicker.

Lorenzo Elliott Semple III was born March 27, 1923, in Mount Kisco, N.Y., to a family with theatrical ties. His uncle was playwright Philip Barry, who wrote “Holiday” and “The Philadelphia Story,” among other hits.

Mr. Semple attended Yale University for a couple of years but left in 1941 to drive an ambulance for the Free French Forces in the Middle East during World War II. After a year, he returned to the United States, where he was drafted into the Army and sent back to the war. During his military service, he earned the Bronze Star Medal.

Finishing his degree at Columbia University, Mr. Semple wrote for magazines and penned two plays that made it to Broadway, including “Golden Fleecing” (1959), a farce about military personnel and a civilian electronics expert who try to break the bank at a Venice gambling casino. A 1961 film version, retitled “The Honeymoon Machine,” starred McQueen, Jim Hutton and Paula Prentiss.

Mr. Semple wrote episodic TV and teamed with producer William Dozier to try to get in on the ground floor of a TV series. They had little success until Mr. Semple, living in Spain, got a cable from Dozier to meet in Madrid.

Dozier told him with derision that ABC wanted them to create a series based on the “Batman” comic books. Mr. Semple recognized that the show could be done in a flippant, satirical manner by making the main character a supremely naive good guy.

Mr. Semple’s Batman hardly resembled the brooding, dark character of recent movies. “Our Batman was unbelievably innocent,” he said on an episode of “Reel Geezers.” “For example, when they’d be chasing the Joker, he would refuse to park if there was a ‘No Parking’ sign. He’d drive around the block and let the Joker get away.”

With the show’s runaway success, Mr. Semple leapt into films. His first assignment on a major project was to adapt the James Grady thriller novel “Six Days of the Condor.” “We cut it down to ‘Three Days of the Condor’ because there wasn’t that much to happen,” he said in the Writers Guild interview. “There wasn’t enough for six days.”

In a pattern that was to play itself out in several movies, Mr. Semple became disengaged when the director, in this case Sydney Pollack, wanted major changes. “I like writing a great deal,” Mr. Semple said. “But when it got to arguing with directors and talking to people, I rapidly lost interest.”

He sometimes agreed with critics who panned films on which he received credit. He felt reviewers were too dismissive of his 1976 remake of “King Kong,” which starred Jeff Bridges and Jessica Lange. “It’s a losing game, remaking a classic,” Mr. Semple said.

His other screenwriting credits included “Pretty Poison” (1968), based on a novel by Stephen Geller, and “The Drowning Pool” (1975), based on a Ross Macdonald novel.

In addition to his wife, Mr. Semple is survived by three children and six grandchildren.

— Los Angeles Times