Jerry Lewis, who died Aug. 20 at 91, was a comic actor whose rubber–limbed pratfalls, squeaky voice and pipsqueak buffoonery made him one of the most uncontainable screen clowns of all time.

His partnership with the suave and assured crooner Dean Martin made them a sensation, easily the most popular comedy team of the mid–20th century. After their bitter break up, which devastated their millions of fans, Lewis embarked on a solo career of dizzying summits and desperate lows, including an addiction to painkillers as years of physical comedy took their toll.

Fascinated by the technical side of film, he became one of the first sound–era comedians to write, direct and star in his own movies. He was credited with laying the groundwork for later comedic writer–director–actors such as Mel Brooks and Woody Allen.

Few comedians have been so beloved and so derided as Lewis, who amassed devoted fans and stunningly hostile reviews from critics. Few have been so accomplished as humanitarians – his annual muscular dystrophy telethons had raised almost $1.5 billion by the late 2000s – or so polarizing as personalities.

Lewis could be candid and coy, insightful and insulting in the same sentence. He was tireless, demanding and insecure – in his own words “a neurotic, temperamental imbecile.” He could also play the charming child, telling interviewers he never felt more than 9 years old.

“An audience is nothing more than eight or nine hundred mamas and papas clapping their hands and saying, ‘Good boy, baby,’ ” he said. “You’ll find that people who had enough ‘Good boy, baby’ from their actual parents rarely turn to comedy.”

Lewis was, for better or worse, one of the most unforgettable entertainers of his generation. In his later years, he battled spinal meningitis, pulmonary fibrosis and diabetes, among other ailments. His death at his home in Las Vegas was confirmed by his publicist, Candi Cazau.

A struggling comedian at 19, Lewis surged to stardom at 20 after partnering with Martin in 1946 at an Atlantic City nightclub. They made 16 films together, including “Jumping Jacks” and “Artists and Models,” and they were major TV stars before breaking up in 1956 at their peak as a duo.

As an actor, Lewis brought an antic joy to hundreds of millions of people who saw him play a role he called “the Idiot,” a cross–eyed innocent who bested bullies despite his nasally voice and gangly appearance.

The Idiot was the sort of uncontrollable character – falling down laundry chutes, breaking furniture and sputtering at the sight of an alluring woman – that set the loony standard for later generations of comedians, including Jim Carrey and Adam Sandler. “The Nutty Professor,” Lewis’ 1963 comedy about a shy professor who invents a formula that turns him into wolfish swinger modeled on Martin, was remade with Eddie Murphy in 1996.

As hosts of the NBC’s “The Colgate Comedy Hour” from 1950 to 1955, Lewis and Martin burst onto the airwaves with an anarchic style unlike most television of that era. Lewis’ goofball utterings – “I like it, I like it” and “La–a–a–dy!” – became national catchphrases.

“You see Jerry Lewis running up to the cameras and into the audience and breaking the rules right off the bat,” said David Schwartz, chief film curator at the American Museum of the Moving Image in New York. “It makes Robin Williams look sedate.”

With a manic energy that often landed him in hospitals from overwork, Lewis made more than 50 films, countless club and television appearances and several popular recordings. His 1956 version of “Rock–a–Bye Your Baby,” a song first popularized by Al Jolson, sold more than 1 million copies.

Lewis was such a financial powerhouse at Paramount Pictures in the 1950s and early 1960s that one executive there was reported to have said, “If he wants to burn the studio down, I’ve got the match.”

He debuted as a director, writer and actor in “The Bellboy” (1960) – a picture set at the Fontainebleau Hotel in Miami Beach – in which he played the hapless title character almost entirely in pantomime. The film was a smash and brought Lewis the cachet to control his next few projects, including “The Ladies Man” (1961), “The Errand Boy” (1961) and “The Nutty Professor.”

As a moviemaker, Lewis was greatly inspired by having worked under director Frank Tashlin, a former animator, on such films as “Cinderfella” (1960) and “The Disorderly Orderly” (1964).

Like Tashlin, Lewis exaggerated sound and sight for affect. In “The Nutty Professor,” the use of amplified sound allows the audience to experience the title character’s hangover after a night of drinking.

When prominent American critics bothered to review Lewis’s films at all, they generally dismissed them as recycled sight gags and plotless pratfalls that lacked continuity.

“In his field of comedy, which happens to be both narrow and rutted, Lewis stands as a sort of witless genius,” critic Harriet Van Horne of the New York World–Telegram and Sun wrote. “He’s the only performer I know who can be both endearing and disgusting in the space of two minutes.”

Lewis gained the grudging respect of some reviewers in 1983 when Martin Scorsese hired him for a dramatic part in “The King of Comedy” as a talk–show host kidnapped by a fan (played by Robert De Niro). In “Funny Bones” (1995), he again won over critics in an unlikable role, playing a comedian who overshadows his son’s comic ambitions.

To some French cinema theorists, Lewis was a “total filmmaker” in the comic moviemaking tradition of Charlie Chaplin and Buster Keaton, who also created and starred in their own projects. The theorists, and even directors such as Jean–Luc Godard, considered Lewis’ broad comic sensibility a comment on an American penchant for excess and male self–doubt and sexual anxiety.

Lewis was contemptuous of the media and, to some degree, American audiences, who he felt never understood his intent as a performer.

He told The Washington Post in 1972 that his humor “is not a sophisticated humor. On the contrary, it’s based on something in its simplest form. Americans are always wondering whether they should laugh if someone gets a pie in the face, if it will demean their character. Europeans don’t think about things like that. They just laugh.”

He was submerged in pie–in–the–face slapstick from his earliest years. He was born Jerome Levitch on March 16, 1926, in Newark, the son of Jewish vaudevillians who performed at New York–area resorts.

He debuted in 1931, when his parents brought him onstage at a hotel to sing the Depression–era anthem “Brother, Can You Spare a Dime?”

Once, he slipped onstage, and his foot went through a footlight bulb. “There was this big laugh, relieved laughter when the audience saw I wasn’t hurt,” he told The Post. “So I went after a second bulb. I’d been hit by the poison dart. I knew how it felt to get a laugh. When my parents got their next booking, the manager had to add, ‘No kicking bulbs out.’ ”

After quitting high school in 1942 – he said it was because of the flagrant anti–Semitism of his principal in Irvington, N.J. – Lewis honed his “record act,” a routine in which he mimed lyrics of operatic and popular songs playing on a phonograph. As an emcee in burlesque houses, he worked to improve his ad–libbing skills before hostile crowds.

In summer 1946, Lewis was doing his record act at the 500 Club in Atlantic City. When the singer on the bill was fired, Lewis suggested the still–obscure Martin as a replacement. The two had performed months earlier at a New York club and began joking around onstage, to the audience’s delight.

At the 500 Club, their act contained the core of what would excite crowds for the next decade: Martin acting seductively toward women, Lewis doing his utmost to interrupt the singer by breaking plates and drinking water from flower vases. Decades later, in the New Yorker, writer James Kaplan likened Lewis onstage to “a chimp on Benzedrine.”

As the Lewis and Martin act grew in popularity, the entertainers signed a movie deal with Hal B. Wallis at Paramount. Wallis saw to it that his new team would stick to a moneymaking formula, playing the same basic characters in every film: Lewis the loon, Martin the ladies’ man. Wallis started them off in secondary roles in “My Friend Irma” (1949), based on the hit radio series.

Despite their on–screen chemistry, the Martin–Lewis relationship grew tense. Lewis often described Martin, nine years his senior, as an older brother. But they competed for attention from peers and women, and Lewis found his partner increasingly aloof and intent on pursuing a separate singing and acting career. Martin, among others, called Lewis mercurial.

“Jerry, who was supposed to be the funny one, couldn’t stand it if Dean got any laughs,” the writer and producer Norman Lear, who wrote for the team, once said. He said Lewis often got physically ill when Martin stole a scene and balked when writers revealed that Lewis alone was not responsible for the jokes on the show.

The Lewis–Martin split was acrimonious. They did not speak to each other for 20 years, until a mutual friend, Frank Sinatra, prodded them to appear together on Lewis’ muscular dystrophy telethon. Dean died in 1995.

After a long run of successes without Martin, Lewis saw his film career plummet in the late 1960s amid audience demand for more topical humor. Studio officials balked at his insistence on total creative control.

Further problems developed in the 1970s. A chain of cinemas he owned went bankrupt, and he wrestled with addiction to painkilling drugs to treat a back injury. The physical pain reportedly left him on the verge of suicide.

Lewis’ movie career went fallow after filming what he considered his unreleased masterpiece. The movie was “The Day the Clown Cried” (1972), in which Lewis played a concentration camp clown who entertains children as they are led to the gas chamber. Considered by those who have seen it as one of the most offensive films ever made, the film was indefinitely withheld from release amid lawsuits among its backers and writers.

His 1944 marriage to Esther Calonico, a big–band singer known as Patti Palmer, ended in divorce in 1980. Survivors include his wife, SanDee Pitnick “Sam” Lewis, whom he married in 1983; five sons from the first marriage, including musician Gary Lewis; and a daughter from the second marriage.

A son from his first marriage, Joseph, died in 2009 of an apparent drug overdose. A complete list of survivors could not be immediately confirmed.

Lewis remained a television star as host of muscular–dystrophy telethons, for which the Academy of Motion Picture Arts and Sciences recognized the actor with its Jean Hersholt Humanitarian Award in 2009.

The telethons featured guest appearances from Charo to Tony Bennett. At the end, Lewis always sang “You’ll Never Walk Alone.” He also had vaudeville acts, acrobats and a procession of youngsters – called “Jerry’s Kids” – suffering from muscular dystrophy.

The telethons were the subject of enduring debate. Television critics and some advocacy groups lambasting them as tasteless spectacles that exploited the children they professed to help.

Some saw the shows as a self–aggrandizing star vehicle for Lewis, who often surrounded himself with performers praising his humanitarianism despite stories generated by some relatives about his womanizing and emotional abuse as a father. He further harmed his reputation with crude remarks about gays and women.

“I have all the strength in the world to fight those morons,” Lewis told The Post about his telethon critics. “Do they want to talk to the 135,000 who are afflicted, who call me their hero? They’ll get killed. And what about the s.o.b.’s who come to you and say, ‘How much do you get out of this action?’ You have to smile, because they have capital punishment in most states.”

He called his rage when discussing the disease “the only productive hate I have.”

Lewis and the Muscular Dystrophy Association parted ways in 2010, under circumstances that remain vague. Five years later, the association said it was ending the telethon for good.

In 1995, Lewis had an acclaimed stage role as the Devil in the musical “Damn Yankees!” At $40,000 a week, he reportedly became the highest–paid performer on Broadway at the time. The New York Times, whose reviewers never much cared for his films, declared, “Jerry Lewis is legitimate at last.”

At this late–career peak, Lewis was still unpredictable in interviews – clowning with a slightly menacing touch. “Let’s put it this way,” he told a Post reporter. “You will remember we met.”

He then threatened to cut the reporter’s tie. He was half–joking.