Garcetti, who will serve as a national campaign co-chair for Biden, had been courted widely by presidential candidates, and he has relationships with many of them. Garcetti, who endorsed Hillary Clinton in 2016, appeared at a King Taco in Los Angeles with Biden in May. But he and Sen. Cory Booker were Rhodes Scholars together, and he is a friend of Pete Buttigieg.

Garcetti said on KTLA in Los Angeles this week that Michael Bloomberg is a “dear friend, and one of the great philanthropists of the world.”

Garcetti had considered running for president himself before deciding a year ago not to. Unlike many high-profile California politicians, Garcetti did not endorse his home-state senator, Kamala Harris, before she dropped out of the race.

Biden, Bernie Sanders and Elizabeth Warren are all running within 2 percentage points of each other in California, according to the latest Real Clear Politics polling average.

It is unclear how much weight Garcetti's endorsement will carry here. Though he is mayor of California’s largest city, Los Angeles has also become synonymous with the state’s housing crisis, a factor that would have worked against him had he mounted his own presidential campaign.

The New York Times first reported news of Garcetti’s endorsement.