On Thursday night, Crystal announced that the band U2 had donated $1 million to relief efforts and that Steve and Connie Ballmer would match that donation and all others made during the telecast. (Steve Ballmer, the former Microsoft chief executive and N.B.A. franchise owner, was the driving force behind the construction of the Intuit Dome arena, where the Los Angeles Clippers play.)

Planning for the concert, which was available to watch on an array of streaming platforms, came together extraordinarily quickly, spearheaded by Irving Azoff, a longtime manager and power broker in music, and his family. Within three days of the fires breaking out, the Intuit Dome had been secured and the event had been announced with the cooperation of Live Nation and AEG Presents, who are usually bitter rivals as the world’s two largest concert promoters.

In a recent phone interview, Azoff said the urgency of the crisis had driven the timing of the concert. With the Grammys on Sunday and the Super Bowl the next weekend, organizers felt that the show had to take place as soon as possible, he said. “This is about fund-raising, and you need to get the money in the bank as quickly as you can,” Azoff added.

Organizers have said that artists were quick to join the effort, with Rod Stewart the first to sign on, followed by Stevie Nicks. They were followed by more than two dozen artists — young stars and older legends alike — with a focus on California-based acts.

“We were very lucky in that our thing was booked almost entirely by people volunteering,” Azoff said.

To close the evening, Lady Gaga said she wanted to bring forward a hopeful song. So she wrote a new one, she said, “just for tonight, just for you.”

The chorus went like this: “All I need is time, to leave it all behind — and keep moving forward.”

Marc Hogan contributed reporting.