Audiences who knew Richard Lewis exclusively from the cringe-making sitcom Curb Your Enthusiasm, which began in 2000 and is still running today, will have a singular image of the neurotic, weather-beaten comic. Coarse-throated, wild-eyed and shuffling, he dressed all in black like Johnny Cash, and had the kind of desiccated appearance that could make Methuselah resemble a boy-band star.

Lewis, who has died aged 76 of a heart attack, played a lightly fictionalised version of himself on the semi-improvised Curb. Like his on-screen self, he was dear friends with the show’s star and creator, Larry David. The pair, born three days apart in the same Brooklyn hospital, met as adolescents at summer camp, where they inspired instant antipathy in one another. Crossing paths in their early 20s on the comedy circuit, a rapprochement led quickly to respect, admiration and even love.

David cast Lewis in the opening episode of Curb, a show characterised by its mix of urbane wit, blithe bad taste and crescendos of mortifying embarrassment. That first half-hour established the duo’s fondly bickering relationship, which provided one of the show’s sweetest and most enduring pleasures.

After David becomes enraged with a fellow cinemagoer who turns out to be Lewis’s latest girlfriend, he is ordered by Lewis to call him “by sundown”. Though their friendship is imperilled, David can’t resist laughing (“‘By sundown’? What are you, Gary Cooper?”) and nor can Lewis, who grudgingly concedes amusement. No amount of outrage or indignation could quell his sense of humour. Often it provided the fuel.

He featured in more than 40 further episodes of Curb, up to and including the current (and reportedly final) twelfth season. Highlights include a squabble over the last bracelet in a jewellery store, which ends with the two men brawling on the pavement outside; an ailing Lewis prevailing upon David to donate one of his kidneys to him; and a recent episode in which he enrages David by writing him into his will.

Lewis also appeared in the one-off HBO mockumentary Larry David: Curb Your Enthusiasm (1999), which followed David plotting a return to stand-up, and from which the series was developed.

Curb enthusiasts outside the US were less familiar with Lewis’s stand-up shows, where his volatility and despair were even more nakedly apparent. He claimed to have coined the formulation “from hell”– as in “The vacation from hell” or “The bar mitzvah from hell” – and the titles of his live TV specials gave fair warning of that infernal bent: I’m in Pain (1985), I’m Exhausted (1988), I’m Doomed (1990) and The Magical Misery Tour (1996).

Anguished he may have been but his onstage persona was highly energised. He stalked the stage, running his hands through his voluminous mane, gesticulating wildly like a scarecrow in a hurricane, his restlessness a challenge for any follow-spot operator. Lewis called himself “a Duracell comic”.

The actor Joe Penny likened him to a “24-hour fire drill”. David Letterman, who welcomed Lewis on to his talk-show some 48 times, told him: “Man, you’re full of transmission fluid! You’re going a thousand miles an hour!”

Not that his material was not intricately shaped and constructed. Robin Williams noted that Lewis’s skill sometimes become apparent only after he had left the stage. “I’ve seen audiences laughing on the freeway,” he said. “He’s gotten many standing ovations once people get to their house.”

The jokes were always at Lewis’s own expense. He claimed to have such a fear of intimacy that he hoped his girlfriend would find out he loved her through word of mouth. An ex whom he was trying to win back invited him to her apartment so he could “watch her blow-torch my name out of her Rolodex”.

His family, whom he characterised truthfully as distant and hard to impress, provided him with a reliable source of humour. When he called his mother to tell her he was making his debut on the prestigious Tonight Show hosted by Johnny Carson, she said: “Who else is on?”

Health was another wellspring of gags. He joked about a friend sending him a colouring book for hypochondriacs: it contained outlines of healthy people, inside which he could draw ailments of his own choosing.

Deep down, he said, he simply didn’t know what he wanted. “My penis is in the shape of a question mark.”

He was born in New York and raised in Englewood, New Jersey, the son of Bill, who ran a catering business, and Blanche (nee Goldberg), a performer in community theatre. He was educated at Dwight Morrow high school and Ohio State University, from which he graduated with a degree in marketing and communications.

He held down day jobs, including one as an advertising copywriter, while crafting his own routines as well as material for fellow comedians. He made his live debut in 1971, and gigged diligently from that moment on.

Two decades before Curb, he played a character loosely based on himself in the TV movie Diary of a Young Comic (1979), which he also wrote.

He became a prime-time sitcom star in Anything But Love, in which he and Jamie Lee Curtis played colleagues at a trend-setting Chicago magazine. The show ran for four seasons between 1989 and 1992, whereas Lewis’s follow-up, Daddy Dearest, about a psychologist living with his father and son, fizzled out after only 13 episodes.

He made guest appearances on other sitcoms including The Larry Sanders Show (1993), Two and a Half Men (2004) and Everybody Hates Chris (2006). Among his sporadic film work was the Mel Brooks spoof Robin Hood: Men in Tights (1993), the Oscar-winning alcoholism drama Leaving Las Vegas (1995), and the screwball comedy She’s Funny That Way (2014).

Clean since 1994, his frankness on stage about his addiction to alcohol and drugs, as well as his struggles with anxiety and depression, earned him the title of the Prince of Pain. “He cuts himself wide open when he works,” said the veteran comic Shelley Berman in 2007. “You can see the guy bleed.”

Lewis was no less honest after learning he had Parkinson’s disease, announcing the diagnosis on social media last year.

He is survived by his wife, Joyce Lapinsky, whom he married in 2005.

• Richard Philip Lewis, comedian, born 29 June 1947; died 27 February 2024