Belzer died Sunday at his home in Beaulieu-sur-Mer, in southern France, his longtime friend Bill Scheft said. Scheft, a writer who had been working on a documentary about Belzer, said there was no known cause of death, but that Belzer had been dealing with circulatory and respiratory issues. The actor Henry Winkler, Belzer’s cousin, tweeted, “Rest in peace Richard.”

For more than two decades and across 10 series — even including appearances on “30 Rock” and “Arrested Development” — Belzer played the wise-cracking, acerbic homicide detective prone to conspiracy theories. Belzer first played Munch on a 1993 episode of “Homicide” and last played him in 2016 on “Law & Order: SVU.”

Belzer never auditioned for the role. After hearing him on “The Howard Stern Show,” executive producer Barry Levinson brought the comedian in to read for the part.

“I would never be a detective. But if I were, that’s how I’d be,” Belzer once said. “They write to all my paranoia and anti-establishment dissidence and conspiracy theories. So it’s been a lot of fun for me. A dream, really.”

From that unlikely beginning, Belzer’s Munch would become one of television’s longest-running characters and a sunglasses-wearing presence on the small screen for more than two decades. In 2008, Belzer published the novel “I Am Not a Cop!” with Michael Ian Black. He also helped write several books on conspiracy theories, about things like President John F. Kennedy’s assassination and Malaysia Airlines Flight 370.

“He made me laugh a billion times,” his longtime friend and fellow stand-up Richard Lewis said Sunday on Twitter.

Born in Bridgeport, Connecticut, Belzer was drawn to comedy, he said, during an abusive childhood in which his mother would beat him and his older brother, Len. He would do impressions of his childhood idol, Jerry Lewis. “My kitchen was the toughest room I ever worked,” Belzer told People magazine in 1993.

After being expelled from Dean Junior College in Massachusetts, Belzer embarked on a life of stand-up in New York in 1972. At Catch a Rising Star, Belzer became a regular performer and an emcee. He made his big-screen debut in Ken Shapiro’s 1974 film “The Groove Tube,” a TV satire co-starring Chevy Chase, a film that grew out of the comedy group Channel One that Belzer was a part of.

Before “Saturday Night Live” changed the comedy scene in New York, Belzer performed with John Belushi, Gilda Radner, Bill Murray and others on the National Lampoon Radio Hour. In 1975, he became the warm-up comic for the newly launched “SNL.” While many cast members quickly became famous, Belzer’s roles were mostly smaller cameos. He later said “SNL” creator Lorne Michaels reneged on a promise to work him into the show.

But Belzer became one of the era’s top stand-ups. He was known especially for his biting, cynical attitude and his witty, sometime combative banter with the audience. As one of the most influential comedians of the ’70s, Belzer was a master of crowd work.

“My style evolved from dealing with drunken people at twelve, one, two in the morning and trying to be like an alchemist and get the lead of their lives and turn it into golden jokes,” Belzer told Terry Gross on “Fresh Air.”

Belzer would later write an irreverent self-help book titled “How to Be a Stand-Up Comic” with advice on things like how to to apologize to Frank Sinatra when you made fun of him onstage or how to deal with hecklers. One of his favorite lines was: “I have a microphone. You have a beer. God has a plan and you’re not in on it.”

Belzer often played a stand-up comic in film, including in 1980s’ “Fame” and 1983’s “Scarface.” He had small roles here and there, including in “Night Shift” in 1982, and “Fletch Lives” in 1989. But Munch would change Belzer’s career.

As ”Homicide” co-creator Tom Fontana said, “Munch was the spice in these dishes,” Belzer told the AV Club. “Munch was based on a real guy in Baltimore who was a star detective, in a way. He would come onto grisly murder scenes, start doing one-liners, because someone had to break the tension. So Munch served a very important function. Not only was he a dissident who said what was on his mind, he kind of had the gallows humor that’s needed in a homicide squad.”

When “Homicide” wrapped in early 1999, Munch called Dick Wolf to see if the character could join another NBC series, “Law & Order,” where Munch had popped up in a few previous episodes. Wolf already had his leads for “Law & Order,” but he wanted Belzer to star in a spinoff. That fall, “Law & Order: SVU” premiered, with Belzer starring alongside Mariska Hargitay and Christopher Meloni in a storyline written as though Munch had transferred from Baltimore to New York.

“Richard Belzer’s Detective John Munch is one of television’s iconic characters,” Wolf said in a statement.

“I first worked with Richard on the ‘Law & Order’/‘Homicide’ crossover and loved the character so much,” Wolf said. “I wanted to make him one of the original characters on ‘SVU.’ The rest is history. Richard brought humor and joy into all our lives, was the consummate professional and we will all miss him very much.”

Belzer is survived by his third wife, the actress Harlee McBride, whom he married in 1985. For the past 20 years, they lived mostly in France, in homes he purchased partially from the proceeds of a lawsuit with Hulk Hogan. In 1985, Belzer had Hogan as a guest on his cable TV talk show “Hot Properties” to perform a chin-lock on him. Belzer passed out, hit his head and sued Hogan for $5 million. They settled out of court.