Jack Sheldon, known to children as one of the voices of “Schoolhouse Rocks” and adults as a master trumpeter who served as music director on “The Merv Griffin Show,” has died at age 88.

Sheldon was the sidekick as well as MD on Griffin’s talk show for 18 years. But his own discography as a band leader added up to more than 20 albums, starting in the late ’50s, when he was part of the west coast bebop movement, continuing through his last release in 2007.

“To all Jack Sheldon fans,” Cynthia Jimenez wrote on the musician’s Facebook page, “on behalf of my sister Dianne Jimenez [his longtime manager], sadly, Jack passed away on December 27. May he rest in peace with all the Jazz Cats in heaven!” No cause of death was given.

Sheldon’s film work included one of the renditions of “The Long Goodbye” heard in the Robert Altman movie of that name, and trumpet playing on Tom Waits’ music for Francis Coppola’s “One from the Heart.” He is the trumpet player heard on Johnny Mandel’s “The Shadow of Your Smile” from the 1965 film “The Sandpiper.”

Sheldon put together a big band for the 1991 feature “For the Boys,” a crew he largely maintained after that for his own shows and recordings.

As a sideman and session player, he worked with everyone from Stan Kenton and Art Pepper to the Monkees.

With Griffin, he told Jazz Times, “It was great in a lot of ways. But mostly because I got to sing, too, which was another whole money thing. Working the show was good money, already. But it got even better when I’d appear on camera on the show and sing and talk, and make more money.”

Decades after his run with Griffin ended in 1986, he was perhaps most recognizable to a mass audience in the 21st century as the voice of the “Schoolhouse Rock” perennials “I’m Just a Bill” and “Conjunction Junction,” to the point that he parodied them as a guest vocalist on episodes of “The Simpsons” and “Family Guy,” respectively. (In the latter instance, he sang “Vagina Junction” as a sex-ed spoof, something that fit with his well known sense of humor.)

Sheldon also appeared in live action TV shows and films as an actor, including “Petticoat Junction,” “Dragnet” and, much later, “The Radioland Murders.” He was the star of his own sitcom, “Run, Buddy, Run,” in 1966-67.

A documentary, “Trying to Get Good: the Jazz Odyssey of Jack Sheldon,” was released in 2008.

A 2011 profile in Jazz Times said that “his trumpet playing is as trim and appealing as it was when he was a boon companion of such West Coast icons as Art Pepper, Chet Baker and Gerry Mulligan.”

Jiminez wrote that a funeral service is scheduled at Forest Lawn in Cypress on Jan. 10.