“It was fun, but hard,” Mr. Caesar said in 1984, looking back on his glory years. “I worked six days a week, putting the script together, working with the writers. The show had to be written by Wednesday night because Thursday we had to put it on its feet. Friday we showed it to the technicians, and Saturday was the show. Sunday was our only day off, and I used to stand under the shower and shake.”

He did more than shake. By the age of 30, Mr. Caesar was not just the king of television, earning $1 million a year; he was also an alcoholic and a pill addict. Under his manic exterior, he recalled in “Where Have I Been?,” his 1982 autobiography, he was distraught and filled with self-hatred, tormented by guilt because he did not think he deserved the acclaim he was receiving.

He was also given to explosive rages. Mr. Caesar once dangled a terrified Mr. Brooks from an 18th-story window until colleagues restrained him. With one punch, he knocked out a horse that had thrown his wife off its back, a scene that Mr. Brooks replayed in his movie “Blazing Saddles.”

By the late 1950s, he was off the air, a victim of changing tastes as well as personal problems. He made a triumphant comeback on Broadway in 1962, playing seven characters in “Little Me,” a musical created by Cy Coleman, Carolyn Leigh and Mr. Simon. (A concert revival of “Little Me” was part of the Encores! series at City Center this month.) A year later, Mr. Caesar held his own among comedy heavyweights like Milton Berle, Mickey Rooney and Jonathan Winters in the hit movie “It’s a Mad, Mad, Mad, Mad World.” But his problems soon got the better of him, and his comeback was short-lived.

Most of the 1960s and ’70s were a struggle. They were also a blur: In writing “Where Have I Been?” Mr. Caesar relied on reporting by his collaborator, Bill Davidson, and the recollections of his family, because there was so much he could not remember. (Twenty-one years later, Mr. Caesar and Mr. Friedfeld wrote a second autobiography, “Caesar’s Hours.” This one was more upbeat, mostly because the focus was Mr. Caesar’s comedy career rather than his personal struggles.)

Image Mr. Caesar, as himself, at home in 2000. Credit... Misha Erwitt

Mr. Caesar was not entirely out of the public eye, even in his dark days. He showed up on television now and then; he appeared in a handful of movies, some memorable (Mr. Brooks’s “Silent Movie”) and some less so (the silly horror comedy “The Spirit Is Willing”); he returned to Broadway in 1971, albeit briefly, in “Four on a Garden,” an ill-fated evening of one-act comedies that also starred Carol Channing. And the release in 1973 of “Ten From Your Show of Shows,” a feature-film compilation of sketches, helped keep his reputation alive. But he continued to flounder.