Mayor Michael Bloomberg helped turn on the 30,000 energy-efficient lights dressing the Christmas tree following a show featuring performances by Jessica Simpson, Sheryl Crow, Josh Groban, British singer Katherine Jenkins and teen pop star Charice.
The 74-foot Norway spruce, donated by Peter and Stephanie Acton of Mahopac, N.Y., will be on view until Jan. 7.
The event took place less than a week after the arrest of a 19-year-old Somali-American man charged in an alleged plot to blow up a car bomb at an Oregon Christmas tree lighting ceremony in Portland.
"It kind of crossed my mind but not enough to keep me away," said 44-year-old Lisa Kingston, who was visiting from Canada with her friend and had wanted to see the event in person after many years of watching it on TV.
Her sentiments were echoed by 41-year-old Bonnie Hixson of Lubbock, Texas.
"It's a sign of our religious freedoms and a sign of our freedom to celebrate," Hixson said. "It's what gets my Christmas season off to a start."
Police prepared for the sizable crowd by blocking off streets and urging people to use mass transit instead of cars to get there.