Jerry Lewis, the hilarious and hugely influential rubber-faced comedian, trailblazing filmmaker, and tireless Muscular Dystrophy fundraiser, died of natural causes Sunday at his home in Las Vegas. He was 91.

Representatives for Lewis confirmed the news to EW.

Lewis was born Jerome Levitch on March 16, 1926, in Newark, N.J., to show-business parents of Russian-Jewish descent. His father was a vaudeville entertainer and his mother was a piano player on the radio, both of whom encouraged their son to a life as a cut-up onstage. By age 5, Lewis was performing in Catskills resorts with his parents. Soon, he developed a solo act mimicking and lip-syncing to records that had audiences laughing through tears.

Lewis’ first taste of fame came in the nightclubs of the then-bustling Jersey Shore vacation paradise, Atlantic City, when, in 1946, he teamed up with another young performer, Dean Martin. Separately, they were unremarkable. Together, they were magic. Martin was a smooth, Italian-American crooner who made female audiences swoon with his swizzle-stick charm; Lewis was the antic manchild — a nervous, twitchy beanpole who would do anything for a laugh. Martin and Lewis soon became one of the biggest acts in the country, raking in money hand over fist.

But beneath their onstage electricity ran an undercurrent of jealousy and resentment. In 1950, Martin and Lewis took their act to TV on the then-popular Colgate Comedy Hour. And their appearances were such a hit with viewers that they were soon summoned to Hollywood to make a string of pictures for Paramount. Most of the movies now seem like dated time capsules loaded with juvenile gags and interminable singing interludes, but it’s impossible to overstate Martin and Lewis’ popularity during the innocent period in American culture.

As Martin’s resentment grew over the growing popularity of his partner, the duo split up in 1956. And while the professional divorce haunted Lewis for decades, it was only after their split that Lewis truly found his voice as a performer. Lewis embarked on a series of high-concept comedies like 1960’s The Bellboy and 1963’s The Nutty Professor (later remade into a hit 1996 film starring Eddie Murphy) that showcased his physical comedy mastery and launched him as a singular (and surprising) talent behind the camera. Lewis’ directing style — which pushed the surreal boundaries of Buster Keaton-esque slapstick saturated with day-glo color film stocks and byzantine set designs — marked him as an auteur that French cinephiles embraced and took as seriously as John Ford and Orson Welles. Americans, on the other hand, still regarded him as the “Hey Lady!” comic.

In 1972, Lewis began working on what was to be his most ambitious — and secretive — project, a feature film that he both directed and starred in called The Day the Clown Cried. The film, which was never released and has sat for decades in a vault, was the story of a circus performer who entertains children at a concentration camp during the Holocaust. Lewis always cited it as his most personal film. And one wonders if now, after his death, it will ever see the light of day.

Lewis should also be remembered as an underappreciated technical innovator — the man who tirelessly tinkered with and invented new film equipment like a latter-day Thomas Edison. One example is Lewis’ patented “video assist system”, whereby a director could watch his actors’ performances on a small monitor and see what sorts of footage they were getting long before film was processed. His technique was a game changer and time-saver that remains the technological gold standard used on film sets to this day. His 1971 book, The Total Film-maker, a hardcover extension of the cinema courses he taught at USC film school (both George Lucas and Steven Spielberg were students), is considered an out-of-print classic still fetching exorbitant sums on eBay.

One passionate fan of Lewis’ how-to manual was Martin Scorsese, who in 1982 tapped Lewis for what is arguably the greatest performance of his career — The King of Comedy’s Jerry Langford. Lewis’ Langford is a late-night talk show host not unlike Johnny Carson, who is kidnapped by an obsessive fan played by Robert DeNiro. It’s a perfect film and a bruise-black comedy performance that Lewis said was easy for him to play because the unlikable character was so much like himself. When asked about this by EW in 2009, Lewis said, “Look, I’m a perfectionist. I’m not always easy to work with. And if someone presses a button, I’ve been known to get crazy.”

Of course, Lewis’ life was about more than just what happened between “action!” and “cut!” In 1953, he proved that he was more than a hyper-caffeinated performer with his involvement in the Muscular Dystrophy Association. Lewis said that he first got involved with the charity after a friend whose nephew had the disease asked if Lewis would make an appeal for donations on The Colgate Comedy Hour. Soon he became the public face of the neuromuscular disorder, raising more than $2 billion for the charity during his annual Labor Day telethons.

In 2009, Lewis — a man who’d given so much to Hollywood but never received a single Oscar nomination — was given the Academy’s Jean Hersholt Humanitarian Award. When EW caught up with him shortly before the ceremony, Lewis discussed his long career and uneasy relationship with the Oscars. When he was asked what he would say when he went onstage to accept the statuette, he replied, “I’m going to make it brief. I’m going to go up there, grab that award, and say, It’s about f—ing time! And walk off.” In the end, Lewis did no such thing. He humbly accepted the honor and thanked the academy, choking back tears.

Lewis’ final film was 2016’s Max Rose.