Neil Simon, 91, who moved from one of early TV’s most successful shows to become the master of Broadway comedies, has died.

Simon “helped redefine popular American humor with an emphasis on the frictions of urban living and the agonizing conflicts of family intimacy,” writes Chirstopher Isherwood in an obituary posted on the website of The New York Times.

Isherwood continues, “His death, at NewYork-Presbyterian Hospital, was announced by his publicist, Bill Evans. The cause was complications of pneumonia, he said. Mr. Simon was also reported to have had Alzheimer’s disease.

“Early in his career, Mr. Simon wrote for television greats, including Phil Silvers and Sid Caesar. Later he wrote for the movies, too. But it was as a playwright that he earned his lasting fame, with a long series of expertly tooled laugh machines that kept his name on Broadway marquees virtually nonstop throughout the late 1960s and ’70s.”

At one point Simon had four plays running simultaneously on Broadway.

Notes Variety, “Simon got his start in TV, as one of the writers on ‘Your Show of Shows,’ the landmark comedic variety show of the 1950s that starred Sid Caesar and Imogene Coca.” The writer’s room for “Shows” was legendary. Besides Simon, the program’s other writers included Woody Allen, Mel Brooks, Larry Gelbart and Carl Reiner.

The hit TV comedy “The Odd Couple” was based on Simon’s play and movie of the same name.

Writes Isherwood in the Times, “Mr. Simon’s early plays, often centered on an antagonistic couple of one kind or another wielding cutting one-liners in a New York apartment, helped set the template for the explosion of sitcoms on network television in the 1970s. (The long-running television show based on his ‘Odd Couple’ was one of the best, although a bum business deal meant that Mr. Simon earned little money from it.)

“A line can be drawn between the taut plot threads of Mr. Simon’s early comedies — a slob and a neatnik form an irascible all-male marriage in ‘The Odd Couple,’ newlyweds bicker in a new apartment in ‘Barefoot in the Park,’ a laid-off fellow has a meltdown in ‘The Prisoner of Second Avenue’ — and the ‘nothing’-inspired, kvetching-character-based comedy of the seminal 1990s sitcom ‘Seinfeld.’”

Says the Associated Press, “Simon’s own life figured most prominently in what became known as his ‘Brighton Beach’ trilogy — ‘Brighton Beach Memoirs,’ ‘Biloxi Blues’ and ‘Broadway Bound’ — which many consider his finest works. In them, Simon’s alter ego, Eugene Morris Jerome, makes his way from childhood to the U.S. Army to finally, on the verge of adulthood, a budding career as a writer.”

In 1991, five years after he wrote “Broadway Bound,” Simon penned “Lost in Yonkers,” which won both a Tony Award for best play and a Pulitzer Prize.

Simon was nominated for an Academy Award for writing the original screenplay for the 1977 comedy hit “The Goodbye Girl.” The movie was also nominated for Best Picture. The only Oscar the film won was for Richard Dreyfuss’ lead performance. However, Simon did win a Golden Globe for writing the movie.

Here’s a must-see short video of Simon talking about how difficult it was to come up with a workable third act to “The Odd Couple”: