
Ok, he was homophobic. But no more homophobic than other people born in 1926: Paul Lynde, Aldo Ray, Tom Tryon, Allen Ginsberg, Cloris Leachman, Charlotte Rae. . .never mind.
[I'm being sarcastic, of course. This is a list of people who were born that year who were gay or gay-friendly, which supports my argument that you can't excuse his homophobia due to his age.]
But in his early days, Jerry Lewis was gay. Or rather, he played gay.
In 1946, the young Borscht Belt comedian Jerry Lewis and the nightclub singer Dean Martin started a comedy act. It spun into a radio program (1949-53), numerous television appearances, and a series of 16 movies, beginning with with My Friend Irma (1946) and ending with Hollywood or Bust (1956).
From the 1920s through the 1960s, many comedians came in pairs: Laurel and Hardy, Abbott and Costello, The Smothers Brothers, Gilligan and the Skipper. They were a relic of Vaudeville, where a "straight man" would set up the joke and a "stooge" would deliver the punchline.

Most comedy duos eliminated the potential for gay subtext by pretending to hate each other, but Dean and Jerry obviously cared for each other. Jerry went even farther, however, hinting to the oblivious Dean that he was in love. And sometimes going beyond hints.
Dean: I want to read this fan letter.
Jerry: You don't need to read it to me. I know what it says. "Dear Mr Martin, you're wonderful, I adore your voice, I dream of you, I sleep with your picture under my pillow."
Dean: How did you know?
Jerry: That's how I feel, too.
Jerry was also extremely physical, always hugging, holding, and trying to kiss Dean, who accepted the displays of affection with some embarrasment. In My Friend Irma Goes West, Dean is rubbing Jerry's chest in a circular motion; Jerry says that it feels good, but he would prefer "bigger circles." Where, precisely, does he want Dean's hand to be?
In their movies and nightclub acts, Dean played the self-absorbed, not-always-faithful "husband," and Jerry the devoted but sneaky "wife." Dean went off to carouse with his card-playing buddies, while Jerry waited at home with dinner in the oven. Sometimes Dean hooked up with women, but Jerry always found a way to sabotage the relationship.
If it was all part of the act, what was it for? What joy did Dean and Jerry expect homophobic 1950s audiences to find in watching unrequited same-sex love?
The pair had a nasty breakup in 1956, and rarely spoke to each other again, except at the funeral of Dean's son, Dean Paul Martin. Dean Martin went on to the famous homoerotic Rat Pack.
But Jerry occasionally commented on their relationship: "It was like a romance"; "We were closer than brothers"; and, in an interview I remember from the early 1970s, "It makes you wonder if there is something to homosexuality."
See also: The Gay Adventures of Jerry Lewis.