Paul Reubens, the comic actor whose bow-tied, childlike alter-ego Pee-wee Herman became an unlikely if almost uncategorizable movie and television sensation in the 1980s, died on Sunday in Los Angeles. He was 70.

His death, at Cedars-Sinai Medical Center, was confirmed on Monday by his longtime representative, Kelly Bush Novak, who said he had “privately fought cancer for years with his trademark tenacity and wit.”

“Please accept my apology for not going public with what I’ve been facing the last six years,” Mr. Reubens said in a statement released with the announcement of his death. “I have always felt a huge amount of love and respect from my friends, fans and supporters. I have loved you all so much and enjoyed making art for you.”

Mr. Reubens had scores of acting credits in a career that began in the 1960s, including roles on “Murphy Brown,” “The Blacklist” and many other television series and in movies like “Buffy the Vampire Slayer” (1992), “Batman Returns” (1992) and “Blow” (2001).

But Pee-wee, a character he created in the late 1970s as a 10-minute bit when he was a member of the Los Angeles comedy troupe the Groundlings, overshadowed all else, morphing into a bizarre and savvy cultural phenomenon, a character aimed (at least in its TV incarnation) at children but tapping into adult sensibilities and ambiguities.

After being disappointed after auditioning unsuccessfully for the “Saturday Night Live” cast in 1980, Mr. Reubens set about creating “The Pee-wee Herman Show,” which was billed as a “live onstage TV pilot.” It had its premiere in early 1981 at the Groundlings Theater in Los Angeles. A national tour followed, and HBO broadcast a version of it as a comedy special in 1981.

Pee-wee started turning up on late-night talk shows, especially “Late Night With David Letterman,” where the juxtaposition of the idiosyncratic Pee-wee and the laid-back, somewhat befuddled Mr. Letterman was comedy gold. “Pee-wee’s Big Adventure,” a feature film directed by Tim Burton, was a hit in 1985.

Then, in 1986, came “Pee-wee’s Playhouse,” a children-friendly version of the world according to Pee-wee that would air on CBS for five years and carve out an enduring place in the memories of 1980s children and, often, their parents.

“Pee-wee’s Playhouse” stands as one of the oddest, most audacious, most unclassifiable shows in television history. The androgynous Pee-wee and a vast collection of human and nonhuman characters — there was, for instance, Chairry, a talking armchair that gave hugs — held forth in each episode about, well, it’s hard to summarize. There was a word of the day. There were bizarre toys. In one episode, Pee-wee married a fruit salad.

The show arrived in the midst of Ronald Reagan’s presidential administration and harked back to another button-down era, the one Mr. Reubens lived as a child: the 1950s.

‘‘I saw it as very Norman Rockwell,” he told The New York Times in 2016, ‘‘but it was my Norman Rockwell version of the ’50s, which was more all-inclusive.”

Laurence Fishburne, S. Epatha Merkerson and other actors of color were in the cast. Gilbert Lewis, who was Black, was the King of Cartoons.

“Not just anybody — the king!” Mr. Reubens said. “That came out of growing up in Florida under segregation. I felt really good about that.”

The show was a world away from standard educational TV for children — its lessons, if any, were delivered through wackiness rather than didactically, and its presentation was decidedly nonlinear.

“I never set out to do a big educational show,” Mr. Reubens told Newsday in 1989. “We’re trying to expose children to as much creativity as we can muster in a half-hour, to be entertaining and to transmit some subliminal messages, like nonconformity isn’t bad.”

The show had not been on long before academics and cultural critics were analyzing its appeal with weighty papers and other commentaries, but Mr. Reubens was having none of that.

“I’ve been almost paranoid about dissecting it too much,” he said, “because the character always has been a kind of instinctual gut thing. I’m able to turn it on, and it just kind of flows. I do what I want and hope it connects.”

The wheels of his career came off in July 1991, when he was arrested on a charge of indecent exposure in an adult movie theater in Sarasota, Fla., where he had grown up. The arrest led to a small fine, but the headlines damaged his reputation.

“Pee-wee’s Playhouse” was in reruns at the time, and CBS pulled them off the air. There were no more new episodes. Mr. Reubens said later that he had been planning a hiatus from show business anyway.

In any case, he took a long break from his alter-ego, but neither Mr. Reubens nor Pee-wee was done.

Mr. Reubens continued to act, receiving an Emmy Award nomination for a guest appearance on “Murphy Brown” in 1995. (His character arc on that show continued for five more episodes.) He also weathered a second scandal: In 2002, he was arrested on a misdemeanor charge of possessing child pornography as a result of images found by the authorities in his collection of vintage erotica. He was sentenced to probation on a reduced charge of possessing obscene material.

“The moment that I realized my name was going to be said in the same sentence as children and sex, that’s really intense,” Mr. Reubens told NBC in 2004. “That’s something I knew from that very moment, whatever happens past that point, something’s out there in the air that is really bad.”

Then, about 2008, some producers began suggesting that he revive the Pee-wee character and some version of the 1980s stage show. He was somewhat reluctant.

“There were age-related issues to it,” Mr. Reubens told The Times in 2010, since he was by then in his 50s. “There were career-standing issues.”

He waffled.

“Every two months, I would change my mind,” he told The Chicago Sun Times in 2010. “And then, finally, one day I woke up and decided, ‘This is it, I’m coming back.’”

The new version of “The Pee-wee Herman Show” opened at Club Nokia in Los Angeles in January 2010, featuring elements of the original stage show and characters from the TV series. It opened on Broadway that November for a limited run.

“Mr. Reubens’s Silly Putty face is a little puttier, but it remains as stretchable as ever,” Charles Isherwood wrote in his review in The Times. “His Popsicle-stick posture retains its comical rigidity; the flapping arms express exasperation and excitement with no loss of tone; the bopping Pee-wee dance is still beach-ball-buoyant. And of course Pee-wee’s restless imagination and childish mood swings are as extravagant as ever.”

A new movie, “Pee-wee’s Big Holiday,” followed in 2016 on Netflix, produced by Mr. Reubens and Judd Apatow. Mr. Reubens told The Times in 2010, when the film was in the early talking stages, that it was no surprise that Pee-wee had endured.

“There’s never been anything from the fans other than, please do more,” he said.

Paul Rubenfeld was born on Aug. 27, 1952, in Peekskill, N.Y., to Milton and Judy (Rosen) Rubenfeld. His mother was a teacher, and his father had been a pilot who, according to The Forward, helped smuggle fighter planes into Israel in 1948 during its war of independence.

The family moved to Sarasota when Paul was 9. His parents ran a lamp store there. Paul had been in school and camp theatrical productions when he graduated to a bigger stage: At 11, he had a key role as the young nephew in a custody dispute in Herb Gardner’s play “A Thousand Clowns,” staged by the Sarasota Players.

“The 12-year-old is played with remarkable assurance and stage-wise technique by Paul Rubenfeld, himself only 11 years old, a genuine talent discovery,” Ray Perkins wrote in a review in The Tampa Bay Times.

“Young Actor Big Crowd Pleaser” read a headline in the same newspaper a few days later over a feature article about him.

He appeared in several other shows with the Sarasota Players and also acted with the Asolo Theater Company (now Asolo Repertory). He spent a year at Boston University after graduating from Sarasota High School in 1970, but then went to the West Coast, studying at the California Institute of the Arts and eventually falling in with the Groundlings, working at a pizza parlor and selling brushes while he developed his comedic skills.

His first film role, uncredited, was as a wedding guest in the 1968 drama “The Brotherhood,” and he had a smattering of other roles before Pee-wee took over. The first name of his enduring character, he said, was borrowed from the tiny Pee Wee harmonica brand. The last name, Herman, was inspired by an irritating childhood acquaintance.

He is survived by a sister, Abby Rubenfeld, and a brother, Luke Rubenfeld.

Just months ago he said he was working on a memoir and a documentary. And in an interview with The Times around that time, one of his last, he reflected on the longevity of Pee-wee, on the adjustments that were made to keep the character fresh, and on how the creative landscape had changed since Pee-wee first appeared some 40 years ago.

“Today, it seems to me, it’s a lot more difficult to stand out,” he said. “You know, if you want to be weird, good luck.”

Jesus Jiménez and Melena Ryzik contributed reporting.