NEW YORK — Playwright Neil Simon, a master of comedy whose laugh-filled hits such as “The Odd Couple,” “Barefoot in the Park” and his “Brighton Beach” trilogy dominated Broadway for decades, died Sunday. He was 91.

Simon died of complications from pneumonia at New York Presbyterian Hospital in Manhattan, said Bill Evans, a longtime friend and spokesman for Shubert theaters.

In the second half of the 20th century, Simon was the American theater’s most successful and prolific playwright, often chronicling middle-class issues and fears. Starting with “Come Blow Your Horn” in 1961 and continuing into the next century, he rarely stopped working on a new play or musical.

The theater world quickly mourned his death , including Tony Award-winning actor and playwright Harvey Fierstein, who tweeted that Simon “could write a joke that would make you laugh, define the character, the situation, and even the world’s problems.”

Matthew Broderick, who in 1983 made his Broadway debut in Simon’s “Brighton Beach Memoirs” and his movie debut in Simon’s “Max Dugan Returns,” added: “I owe him a career. The theater has lost a brilliantly funny, unthinkably wonderful writer. And even after all this time, I feel I have lost a mentor, a father figure, a deep influence in my life and work.”

For seven months in 1967, he had four productions running at the same time on Broadway: “Barefoot in the Park,” “The Odd Couple,” “Sweet Charity” and “The Star-Spangled Girl.”

Even before he launched his theater career, he made history as one of the famed stable of writers for comedian Sid Caesar that also included Woody Allen, Mel Brooks and Carl Reiner.

Simon was the recipient of four Tony Awards, the Pulitzer Prize, the Kennedy Center honors (1995), four Writers Guild of America awards and an American Comedy Awards lifetime achievement honor. In 1983, he had a Broadway theater named after him when the Alvin was rechristened the Neil Simon Theatre.

In 2006, he won the Mark Twain Prize for American Humor, which honors work that draws from the American experience.

In a 1997 interview with The Washington Post, Simon reflected on his success: “I know that I have reached the pinnacle of rewards. There’s no more money anyone can pay me that I need. There are no awards they can give me that I haven’t won. I have no reason to write another play except that I am alive and I like to do it,” he said.

The bespectacled, mild-looking Simon was a relentless writer — and rewriter.

“I am most alive and most fulfilled sitting alone in a room, hoping that those words forming on the paper in the Smith-Corona will be the first perfect play ever written in a single draft,” Simon wrote.

Simon was born Marvin Neil Simon in New York and was raised in the Bronx and Washington Heights. He was a Depression-era child, his father, Irving, a garment-industry salesman. He was raised mostly by his strong-willed mother, Mamie, and mentored by his older brother, Danny, who nicknamed his younger sibling, Doc.

Simon attended New York University and the University of Colorado. After serving in the military in 1945 and 1946, he began writing with his brother for radio in 1948, and then for television, a period in their lives chronicled in Simon’s 1993 play, “Laughter on the 23rd Floor.”

Simon was married five times. His first wife, Joan Baim, died of cancer in 1973, after 20 years of marriage. The playwright then married actress Marsha Mason, and they divorced in 1982. He married his third wife, Diane Lander, twice — once in 1987-1988 and again in 1990-1998 — and married his fourth wife, actress Elaine Joyce, in 1999.

He also is survived by three daughters, three grandchildren and one great-grandson.