Elon Musk declared final month that the federal authorities was engaged in “totally insane” exercise, claiming with out proof that it had distributed $100 billion to folks with out Social Safety numbers.

Two days after Mr. Musk’s feedback, certainly one of his key lieutenants, Steve Davis, started urgent the Social Safety Administration for data. Mr. Davis known as the company’s leaders to insist they provide a younger engineer from Mr. Musk’s so-called Division of Authorities Effectivity entry to databases that contained delicate details about People.

Mr. Davis’s demand was “unprecedented,” Tiffany Flick, a former Social Safety official, stated in a sworn statement this month for a lawsuit filed by federal workers making an attempt to dam entry to the information. She added that she might really feel Mr. Davis develop impatient within the hours earlier than the DOGE engineer was ultimately permitted to research “the final delusion of supposed widespread Social Safety fraud.”

Deploying employees into federal companies is only one job that Mr. Davis has carried out lately for Mr. Musk, because the world’s richest man continues an all-out effort to reshape the U.S. authorities. At each flip, Mr. Davis has backed his boss, laying the groundwork for price chopping in the course of the presidential transition, slashing range initiatives, assembly lawmakers and serving to to ship a governmentwide “Fork within the Street” e mail that urged employees to resign.

These actions display how Mr. Davis, 45, has successfully change into the day-to-day chief of DOGE. He has extra energy than Amy Gleason, the Trump administration’s appearing DOGE administrator, two folks near the hassle stated, including that Ms. Gleason has typically been in the dead of night about Mr. Davis’s selections.

How Mr. Davis received to this place is hardly a secret. For greater than 20 years, the engineer has devoted himself to fulfilling Mr. Musk’s needs, following the billionaire to his numerous corporations, together with the rocket maker SpaceX and the social media platform X. Mr. Davis wholeheartedly believes Mr. Musk will result in humanity’s progress, in keeping with interviews with 22 pals, former colleagues and authorities officers.

For Mr. Musk, Mr. Davis represents the best worker — an engineer who will throw himself at any job, even when he has no experience within the space, two former colleagues stated. Mr. Musk has particularly praised Mr. Davis’s skill to excise waste, as soon as likening his lieutenant to a cancer-killing remedy.

“Steve is like chemo,” Mr. Musk stated at a transition assembly earlier than President Trump took workplace. “Slightly chemo can save your life; a whole lot of chemo might kill you.”

Mr. Musk and Mr. Davis have bonded deeply over price cuts. At SpaceX, Mr. Davis devised methods to construct rockets extra cheaply. He additionally oversaw layoffs at Twitter, which was renamed X. At DOGE, he’s coordinating engineers and legal professionals to seek out $2 trillion that Mr. Musk has promised to get rid of from the federal price range.

Mr. Davis is so loyal to Mr. Musk that he and his associate, Nicole Hollander, 42, who joined the Common Providers Administration to chop federal actual property prices, have arrange a base of operations on the company’s sixth flooring in Washington. It’s guarded by a full safety element, three company workers stated.

Adam Inexperienced, a progressive organizer who befriended Mr. Davis a couple of decade in the past once they lived in Washington, stated Mr. Davis was as soon as a “enjoyable outside-the-box thinker,” who had was a “blind servant” to Mr. Musk.

Mr. Davis, Mr. Musk, Ms. Hollander and the White Home didn’t reply to requests for remark.

Mr. Davis started working for Mr. Musk in 2003, when the tech entrepreneur plucked him out of a Stanford aeronautics graduate program. Mr. Davis turned the 14th employee at SpaceX. He shortly endeared himself to Mr. Musk by discovering inexpensive methods to develop rocket elements, together with making a shuttle steering machine for a hundredth of the worth.

His frugality led to errors. In 2007, Mr. Davis eliminated parts from SpaceX’s Falcon 1 rocket that prevented gasoline from sloshing contained in the car, three former colleagues stated. That induced the gasoline to unbalance the rocket throughout a take a look at flight, and it shut down midair earlier than reaching orbit.

By 2008, Mr. Davis had moved to Washington and was later named SpaceX’s director of superior tasks. He had a broad vary of duties on the firm, together with discovering land round Boca Chica, Texas, for what would change into Starbase, SpaceX’s rocket launch facility.

On the aspect, Mr. Davis pursued an economics doctorate and opened Mr. Yogato, a frozen yogurt store that supplied reductions to clients who answered trivia questions. He additionally helped create a Jewish life-style web site, Collect the Jews, and joined the board of the Atlas Society, a nonprofit devoted to the teachings of the libertarian writer Ayn Rand.

In 2018, Mr. Musk appointed Mr. Davis to guide the Boring Firm, a start-up that goals to construct tunnels underneath main metropolitan areas to ease congestion.

“Generally there may be virtually zero R&D in tunnels in America,” Mr. Davis said at a presentation for the corporate that 12 months. “So making an attempt new issues is definitely useful for us.”

The Boring Firm opened a tunnel in Las Vegas in 2021, however has run into regulatory roadblocks elsewhere. That annoyed Mr. Musk, who berated Mr. Davis and threatened to fireplace him, three individuals who have labored with Mr. Davis stated. The stress weighed on Mr. Davis, and he typically pulled out his hair, 5 folks near him stated.

After Mr. Musk purchased Twitter in 2022, Mr. Davis helped slash the corporate’s prices, telling those who he hoped to get rid of greater than $500 million. He was so devoted that on some nights, he stayed with Ms. Hollander and their new child child at Twitter’s San Francisco workplace.

Mr. Davis additionally oversaw the set up of a private rest room for Mr. Musk there, telling one worker to not hassle acquiring a development allow.

“We don’t must observe the foundations,” Mr. Davis stated, in keeping with a 2023 lawsuit from former Twitter employees who accused the corporate and Mr. Musk of violating the phrases of their employment agreements.

Some employees complained about Mr. Davis’s price chopping to Linda Yaccarino, who turned X’s chief govt in 2023, and requested her to rein him in, two folks with information of the discussions stated. He left X quickly after.

When Mr. Musk stumped for Mr. Trump in Pennsylvania throughout final 12 months’s presidential marketing campaign, Mr. Davis relocated to accommodations in Philadelphia and Pittsburgh to supervise an excellent PAC that Mr. Musk had backed, three folks stated. Mr. Davis helped conceive a $47-a-head petition that Mr. Musk promoted to prove Trump voters, and cited his Twitter price chopping as a manner of doing issues cheaply on the tremendous PAC.

After Mr. Trump received the election, Mr. Davis joined a transition “touchdown workforce” and interviewed candidates for Mr. Musk’s effectivity fee. He additionally met with companies that employed engineers to evaluate the technical expertise that DOGE may faucet, three authorities officers stated. Mr. Musk included Mr. Davis in recruiting pitches to potential authorities hires, in keeping with an inner e mail seen by The New York Instances.

After Mr. Trump’s inauguration, Mr. Davis pushed administration officers to let him e mail all authorities workers directly, two folks with information of his efforts stated. That led to a January e mail blast often known as the “Fork within the Street,” which included a governmentwide resignation supply.

When leaks in regards to the resignation supply circulated within the media, Mr. Davis rebuked officers for not controlling their staffs and accused them of embarrassing Mr. Musk, two folks stated.

Mr. Davis pushes for Mr. Musk’s priorities every day with Mr. Trump’s advisers, two folks with information of the conversations stated. He has alerted administration officers to range, fairness and inclusion packages which are focused for cuts and people to be faraway from authorities boards.

Mr. Davis, who may be blunt and undiplomatic, particularly in late-night texts, has additionally clashed with a few of Mr. Trump’s employees. He and his colleagues upset some White Home advisers with the way in which DOGE tried to put a few of their recruits on the Pentagon, three folks stated.

All through, Mr. Davis has studiously prevented consideration. Mr. Musk and the White Home haven’t talked about him. In Washington, Mr. Davis largely prevented having his image taken till this month, when he spoke on the DOGE Caucus, a Home of Representatives group that works with the cost-cutting job pressure.

“Wrapped an incredible assembly with @elonmusk and Steve Davis on their objectives for the @DOGE,” Consultant Aaron Bean, Republican of Florida, posted on X. The message included a photograph of Mr. Davis holding a microphone and smiling beside Mr. Musk.

Reporting was contributed by Kirsten Grind, Eric Schmitt, Jonathan Swan and Maggie Haberman. Susan C. Beachy contributed analysis.