Liza Minelli, ex-Yankee manager Joe Torre, ABC News' Diane Sawyer and even former President Bill Clinton were among the attendees.
"Genius is rare enough, but a good-hearted genius is rarer still. A good-hearted, humble and hilarious genius is almost unheard of," Clinton said of Hamlisch.
Hamlisch composed or arranged hundreds of scores for musicals and movies, including "A Chorus Line" on Broadway and the films "The Sting," "Sophie's Choice," "Ordinary People" and "The Way We Were." His work on "A Chorus Line" earned him both a Tony and a Pulitzer Prize.
His musical life came to an end Aug. 6 in Los Angeles at age 68 after a short illness. He is survived by his wife of 26 years, Terre.
The Associated Press contributed to this report.