King was born Irwin Alan Kniberg in Brooklyn on December 26, 1927 to Russian immigrants. He was an early protégé of Milton Berle and was well known for his appearances on The Ed Sullivan Show and The Tonight Show. He was also a prolific nightclub performer and a renowned member of the Friars Club, which he joined in 1945. Among his many high profile assignments, King emceed President John F. Kennedy's inaugural party and hosted the 1972 Academy Awards. In January 2004, he was honored as a Legend of Comedy and performed in the second annual Nightlife Awards event at The Town Hall.
He appeared in 29 films and numerous television shows, founded the Alan King Tennis Class professional tennis tournament in Las Vegas in the 1970s, and authored five books including his 1996 autobiography Name-Dropping: The Life and Lies of Alan King. His charity work included fund raising for the Nassau Center for Emotionally Disturbed Children on Long Island, the establishment of a chair in dramatic arts at Brandeis University, and the founding of the Alan King Diagnostic Medical Center in Jerusalem.
King co-starred in the 1965 City Center revival of Guys and Dolls and in the Broadway production of The Impossible Years. Among his credits as a producer were The Lion in Winter and the 1966 revival of Dinner at Eight. In 2002, King played the title role in Marsha Lebby and John Lollos's Mr. Goldwyn, which ran Off-Broadway at the Promenade Theatre.
He is survived by his wife Jeanette, two sons, a daughter, and seven grandchildren.