Now, he’s doing the attacking on Biden’s behalf.

Campaigns want surrogates “to be doing both supportive, affirmative messages around the record and agenda. You also want them to take the fight to the other party,” said a Biden adviser of their emerging stable of influential surrogates, speaking freely on the condition of anonymity. On Newsom directly, the adviser said: “Our view is he’s been doing a good job on both.”

While it’s customary for governors to line up behind their party’s president, Newsom has gone to even greater lengths in recent months to demonstrate his fealty and offer up his services to help for 2024.

The California governor hopscotched the Bay Area for nearly 36 hours this week to greet Biden at the airport, speak about the administration’s climate policy at a Palo Alto nature preserve, chat artificial intelligence in San Francisco and co-headline a reelection fundraiser for the president across the Golden Gate in the deep-pocketed woodlands of Marin County.

Appearing before more than 100 donors gathered Tuesday afternoon in Kentfield, Newsom piled on praise, calling Biden a “remarkable leader” who needs another four-year term.

“I am here, Mr. President, as a proud American, as a proud Californian, mesmerized by not just your faith and devotion to this country, and the world we’re trying to build, but by your results, by your action, by your passion, by your capacity to deliver,” he said.

Biden traded compliments with him from behind the microphone at the AI event, calling Newsom his “buddy” and “one of the best governors I’ve ever worked with.”

As the trip wrapped Wednesday, Biden advisers and several aides felt that Newsom and Biden lifted each other up during the visit. And officials back in Washington were commenting to each other about how well things had gone with Newsom, according to people with knowledge of the conversations.

According to aides and close allies, Newsom has coordinated with Biden’s team on everything from his own PAC to national travel to even his major interviews — all with the idea of ensuring he doesn’t fall out of step with the party’s leader. Newsom has long personally maintained a strong relationship with Biden himself, but he previously rubbed some presidential aides and allies the wrong way by calling out the Democratic Party as sluggish in the face of the concerted GOP attacks. Lately, he checks in regularly with Biden’s close-knit circle of top advisers and last year bonded over family and education policy with first lady Jill Biden on a trip to Washington.

“Gov. Newsom loves that man — loves him,” said Anthony York, a Newsom senior adviser.

Newsom sees a role for himself in elevating Biden’s sweeping policy wins, such as the infrastructure, veterans’ health care and computer chips legislation.

“He has a deep respect for him and really does believe that the things he has accomplished — from the IRA to the [infrastructure bill] — are transformational pieces of legislation that will reshape our country for the next 50 years,” York said.

The Biden world, in turn, has come to view the swaggering 55-year-old as an important ally, a younger official comfortable in the ways of modern verbal combat and unafraid to go on offense against the president’s biggest detractors. Pointing to Newsom’s haymakers at former President Donald Trump and Florida Gov. Ron DeSantis, the leading Republican candidates for 2024, the Biden adviser added: “That is being a good surrogate. And appreciated.”

Rep. Anna Eshoo (D-Calif.), who appeared at events this week with Biden and Newsom, said dealing with California’s recent spate of disasters, including historic drought and wildfires, helped the pair forge a tighter relationship. “Steel comes through a great deal of stress,” she said.

It’s too early to know how Newsom might be deployed in the campaign. He’s used his own list of supporters to raise money online and stand up events. He traveled to Washington for Biden’s finance kickoff with national co-chair Jeffrey Katzenberg, telling aides he felt it was important to be there in person as an added demonstration of his support.

Newsom helped raise about $2 million at the event Tuesday in Kentfield. His running tally of online fundraising for Biden is approaching $500,000, an aide said.

It wasn’t always so copacetic between the two camps. In addition to earlier whispers about his presidential ambitions, Newsom’s broadsides against the party fueled critiques he wasn’t a team player.

Last year, some White House officials and Biden allies were openly annoyed when Newsom went out after the Supreme Court’s Dobbs decision on abortion got leaked and asked, “Where the hell’s my party?” The critiques arrived at a vulnerable time for Biden, who was facing persistent questions about his age, confronting what was expected to be a brutal 2022 midterms and suffering from soft polling.

Officials from the White House, DNC and even then-House Speaker Nancy Pelosi, who is close with Newsom, took his words personally. Some accused him of grandstanding at their expense. The tension was more acute given Biden’s stumping for Newsom during the attempted recall of the governor.

Newsom and advisers studiously maintained he never had plans to challenge Biden in 2024 — and Newsom himself relayed that message to the White House repeatedly. But tensions still simmered. Then came the governor’s time to feel burned after Biden took the unusual step of endorsing a farmworker unionization bill that Newsom had expressed skepticism about — jamming him in the process.

Some viewed the dustup between the two Democrats as ironic, given that Newsom had managed to maintain a cordial report with Trump while he was in office.

“A lot of this was staff driven,” a person close to the Biden White House said of the pair. “On the principal level, it’s strong — and I would say it always has been. The president likes Gavin, and he the president.”

Newsom’s appearance on Hannity, as well as his frequent sparring with DeSantis, reinforced within Biden world the role the governor could play in taking the fight to GOP turf.

“Newsom pointed out inflation was high in other countries, too. He kind of melted Hannity’s brain,” another Biden adviser noted.

In the recent interview on Fox News, Newsom also portrayed a close relationship with Biden, saying they are in frequent communication. It was the kind of approach that has helped build trust among the president’s loyalists. And it hinted at the lengths Newsom had gone to read them in on his own political activity.

According to people familiar with the events, Newsom and aides gave the White House a heads up around the launch of his political committee and solicited a supportive prepared statement from DNC Chair Jaime Harrison. When Newsom traveled across the South, pummeling red states and touting Biden’s work in areas where Democrats are scarce, Newsom steered clear of South Carolina — in part to avoid drama around 2024.

Newsom also has informed Biden advisers about his big national interviews, such as the one with Hannity, and offered a heads up after the fact so they weren’t caught off guard by anything he said. But it’s been his broadsides that have garnered the most attention — inside and outside the White House.

“Gavin Newsom enjoys the arena,” Eshoo said. “In politics, you value someone that knows how to not only throw a punch, but take a punch.”