George Carlin, who died Sunday at 71, was both lionized and (briefly) prosecuted for endangering the youth of America with sheer profanity, but his real talent lay in making existential anger and despair into a compelling topic for stand-up comedy.

His routines veered from the wry acerbity of Mark Twain to the profane mordancy of Lenny Bruce, the comedian Carlin often cited as his greatest inspiration. From the early 1970s, when his first solo records began appearing, he was at the top of the nation’s stand-up roster.

One of his early records, “Class Clown” (1972) included the routine “Seven Words You Can Never Say on Television.” After it was broadcast on New York’s WBAI-FM, an offended listener sued, sparking a 1978 Supreme Court decision allowing the Federal Communications Commission to censor the airwaves.

“So my name is a footnote in American legal history, which I’m perversely kind of proud of,” he told the Associated Press earlier this year.

Bearded and in recent years balding, Carlin maintained an active touring schedule and appeared just last week at the Orleans Casino & Hotel in Las Vegas. His always-fertile mind overflowed with ideas, and he had taken to recording them in a series of helter-skelter best sellers starting with “Brain Droppings” (1997). The books included poems and memories, but mostly funny stuff, such as: “Why do they lock gas station bathrooms? Are they afraid someone will clean them?”

Carlin’s career went through a number of phases, but he liked to say he was truest to himself as the reflective prowler, stalking the stage as a primate, grunting and talking to himself before coming out with some brilliant set of observations.

In the early days, he worked in radio, and in the 1960s had a fairly conventional stand-up act in which he impersonated various on-air personalities of his own creation, such as “Al Sleet, your hippy-dippy weatherman. Hey baby what’s happening? Tonight’s forecast is … dark, continued dark, with more light toward morning.” He was a snappy dresser and a regular on Johnny Carson’s “Tonight Show.” In 1967, he complained to the New York Times about the hypocrisy of the Establishment, yet said he’d cut caustic criticism from his own act.

But in 1970, while recovering in the hospital from an operation, he decided to ramp up the bile. “I realized I was a monologist,” he told the Christian Science Monitor in 1973. “I said to myself, ‘Why not say the things and do the things that are really in your mind and in your heart?'” The mature Carlin style was born. Gone were the close-cropped hair and business suits; bring on the wild-eyed, long-haired, snarling hippie. He began performing with a cardboard cutout of his former persona, his opening line a seemingly contemplative “Hi. I’m George Carlin. I don’t really have a beginning.”

What followed were several years of wild success, during which Carlin became a household name. His only competition for hip profanity was Richard Pryor, a more Rabelaisian figure who broke through at the same moment. Robin Williams and Steve Martin lay a few years in the future, but a new golden age of comedy was aborning.

He was born May 12, 1937, in New York (“God winced,” Carlin wrote). Raised in an Irish enclave of Morningside Heights, Carlin never knew his father, an advertising salesman at the old New York Sun who died while Carlin was a toddler. Carlin drew plenty of fodder from his days as an altar boy with street smarts, a self-described “Irish Macho.” He once said, “I was around smack as a kid, and around lush, and around grass, and the only thing I ever went for was my grass.” In the 1970s, he would expand his palette with a self-described massive cocaine habit that fueled some of his most popular work.

Disillusioned with religion at 14, he dropped out of parochial high school and at 17 signed up with the Air Force. He became a radar mechanic and was stationed at Shreveport, La., where he moonlighted as a disc jockey. He claimed to have been brought before courts martial three times, but in 1957 received a general discharge. He got a job as an announcer at a radio station in Boston, where he was fired for making a weekend marijuana run to New York in the station’s news van the same weekend that riots swept a Massachusetts prison.

He moved to Texas, where he took odd jobs including marketing director for peanut brittle, then teamed up with a local newscaster, Jack Burns. They took their act to Hollywood in 1962, and within months scored an appearance on the “Tonight Show.” The act didn’t last, but it was while on tour with Mr. Burns in Chicago that Carlin went to see Lenny Bruce perform. He later hailed Bruce as “the immortal enemy of cant and hypocrisy and pseudo-liberalism, which is just another form of hypocrisy.” But it was as a more mild-mannered creator of impressions that Carlin became a fixture of television comedy in the 1960s.

He tried out his new monologist persona at the 1970 Washington, D.C., Radio and Television Correspondents’ Association Dinner — attended by president Nixon — and it was an immediate hit. He dedicated “Class Clown,” with its seven deadly words, to Leonard Schneider, a.k.a. Lenny Bruce. In 1975, he was the first guest host of “Saturday Night Live,” and two years later he did his first-ever HBO comedy special, which became biennial.

Carlin appeared in a small roles in a number of films, including “With Six You Get Eggroll” (1968), “Car Wash” (1976), “Bill and Ted’s Excellent Adventure” (1989), and a dozen more, including the voice of Fillmore the hippie VW Microbus in “Cars” (2006). Adults who as adolescents thrilled to his seven deadly words were pleasantly surprised to find him entertaining their toddlers as the mild-mannered narrator of “Shining Time Station” (“Thomas the Tank Engine”) from the early 1990s.

Despite his success and his whimsy, there was never much doubt that Carlin’s humor came from a well of despair.

“This species is a failure that has organized itself incorrectly, and it’s stuck and will never get out of it because the forces that keep it this way are much too powerful to change,” he told the Denver Post in 1996. “So I gave up on this species, and I kind of try to look at it from a distance, but I can’t completely give up because I’m a part of it. So there’s this tension, and that creates a kind of anger that is easy to theatricalize.”

His first wife, Brenda, whom he married in 1961, died in 1996. He is survived by his second wife, Sally Wade, and a daughter, Kelly Carlin McCall.