Kevin Spacey led the finale of Give Peace A Chance
Lennon's younger son Sean joined a bill which included Craig David, Moby, Rufus Wainwright and Lou Reed at the Radio City Music Hall.
Recent events had transformed the concert into a benefit for the casualties of the 11 September attacks on the US - and a statement of pride in New York City itself.
Actor Kevin Spacey - who hosted the show and sang Mind Games - said: "A despicable act of blind hatred has failed completely to tear us apart.
"It has united us in our shared pain and in our resolve."
The show started with a gospel version of Imagine from Yolanda Adams.
The audience cheered when pictures of New York firefighters were beamed on to the stage behind the Stone Temple Pilots during their version of Revolution.
Sean Lennon sang Across The Universe and This Boy with Rufus Wainwright.
British artist Craig David, accompanied only by an acoustic guitar, sang Come Together and Cyndi Lauper, performing live from the Strawberry Fields memorial in Central Park, performed Strawberry Fields Forever.
The concert closed with a medley of Give Peace A Chance and Power to the People, with the performers - who included actors Kevin Bacon, James Gandolfini and Ben Stiller - and musicians forming a conga line up the aisle of the Radio City hall.
The concert had originally been scheduled for 20 September - but was postponed after the attacks on the US.
Money raised by the show will go to the American Red Cross, and police and firefighters' charities.
Before the show Lennon's widow Yoko Ono said: "There's all this talk about numbers, of the thousands of people who died.
"They're not numbers. Each person has a family and friends who miss the person and love the person.
"I hope that singing John's songs, songs that were written by someone who was also a victim of violence, will somehow help people.
"John's music always inspired people and gave power to people and this is what we need in New York at this point."
Lennon was murdered in New York almost 21 years ago, but the city's devotion to his words and music reflects his enduring power as a pop culture icon.
The show was televised live on the WB and TNT television networks.