Elon Musk declared last month that the federal government was engaged in “utterly insane” activity, claiming without evidence that it had distributed $100 billion to people without Social Security numbers.
Two days after Mr. Musk’s comments, one of his key lieutenants, Steve Davis, began pressing the Social Security Administration for information. Mr. Davis called the agency’s leaders to insist they give a young engineer from Mr. Musk’s so-called Department of Government Efficiency access to databases that contained sensitive information about Americans.
Mr. Davis’s demand was “unprecedented,” Tiffany Flick, a former Social Security official, said in a sworn statement this month for a lawsuit filed by federal employees trying to block access to the data. She added that she could feel Mr. Davis grow impatient in the hours before the DOGE engineer was eventually permitted to investigate “the general myth of supposed widespread Social Security fraud.”
Deploying staff into federal agencies is just one task that Mr. Davis has carried out recently for Mr. Musk, as the world’s richest man continues an all-out effort to reshape the U.S. government. At every turn, Mr. Davis has backed his boss, laying the groundwork for cost cutting during the presidential transition, slashing diversity initiatives, meeting lawmakers and helping to send a governmentwide “Fork in the Road” email that urged workers to resign.
Those actions demonstrate how Mr. Davis, 45, has effectively become the day-to-day leader of DOGE. He has more power than Amy Gleason, the Trump administration’s acting DOGE administrator, two people close to the effort said, adding that Ms. Gleason has sometimes been in the dark about Mr. Davis’s decisions.
How Mr. Davis got to this position is hardly a secret. For more than 20 years, the engineer has devoted himself to fulfilling Mr. Musk’s desires, following the billionaire to his various companies, including the rocket maker SpaceX and the social media platform X. Mr. Davis wholeheartedly believes Mr. Musk will bring about humanity’s progress, according to interviews with 22 friends, former colleagues and government officials.
For Mr. Musk, Mr. Davis represents the ideal employee — an engineer who will throw himself at any task, even if he has no expertise in the area, two former colleagues said. Mr. Musk has especially praised Mr. Davis’s ability to excise waste, once likening his lieutenant to a cancer-killing treatment.
“Steve is like chemo,” Mr. Musk said at a transition meeting before President Trump took office. “A little chemo can save your life; a lot of chemo could kill you.”
Mr. Musk and Mr. Davis have bonded deeply over cost cuts. At SpaceX, Mr. Davis devised ways to build rockets more cheaply. He also oversaw layoffs at Twitter, which was renamed X. At DOGE, he is coordinating engineers and lawyers to find $2 trillion that Mr. Musk has promised to eliminate from the federal budget.
Mr. Davis is so loyal to Mr. Musk that he and his partner, Nicole Hollander, 42, who joined the General Services Administration to cut federal real estate costs, have set up a base of operations on the agency’s sixth floor in Washington. It is guarded by a full security detail, three agency employees said.
Adam Green, a progressive organizer who befriended Mr. Davis about a decade ago when they lived in Washington, said Mr. Davis was once a “fun outside-the-box thinker,” who had turned into a “blind servant” to Mr. Musk.
Mr. Davis, Mr. Musk, Ms. Hollander and the White House did not respond to requests for comment.
Mr. Davis began working for Mr. Musk in 2003, when the tech entrepreneur plucked him out of a Stanford aeronautics graduate program. Mr. Davis became the 14th employee at SpaceX. He quickly endeared himself to Mr. Musk by finding less expensive ways to develop rocket parts, including making a shuttle steering device for a hundredth of the price.
His frugality led to mistakes. In 2007, Mr. Davis removed components from SpaceX’s Falcon 1 rocket that prevented fuel from sloshing inside the vehicle, three former colleagues said. That caused the fuel to unbalance the rocket during a test flight, and it shut down midair before reaching orbit.
By 2008, Mr. Davis had moved to Washington and was later named SpaceX’s director of advanced projects. He had a broad range of responsibilities at the company, including finding land around Boca Chica, Texas, for what would become Starbase, SpaceX’s rocket launch facility.
On the side, Mr. Davis pursued an economics doctorate and opened Mr. Yogato, a frozen yogurt shop that offered discounts to customers who answered trivia questions. He also helped create a Jewish lifestyle website, Gather the Jews, and joined the board of the Atlas Society, a nonprofit dedicated to the teachings of the libertarian author Ayn Rand.
In 2018, Mr. Musk appointed Mr. Davis to lead the Boring Company, a start-up that aims to build tunnels under major metropolitan areas to ease congestion.
“In general there is almost zero R&D in tunnels in America,” Mr. Davis said at a presentation for the company that year. “So trying new things is actually helpful for us.”
The Boring Company opened a tunnel in Las Vegas in 2021, but has run into regulatory roadblocks elsewhere. That frustrated Mr. Musk, who berated Mr. Davis and threatened to fire him, three people who have worked with Mr. Davis said. The stress weighed on Mr. Davis, and he sometimes pulled out his hair, five people close to him said.
After Mr. Musk bought Twitter in 2022, Mr. Davis helped slash the company’s costs, telling people that he hoped to eliminate more than $500 million. He was so dedicated that on some nights, he stayed with Ms. Hollander and their newborn baby at Twitter’s San Francisco office.
Mr. Davis also oversaw the installation of a personal bathroom for Mr. Musk there, telling one employee not to bother obtaining a construction permit.
“We don’t have to follow the rules,” Mr. Davis said, according to a 2023 lawsuit from former Twitter workers who accused the company and Mr. Musk of violating the terms of their employment agreements.
Some workers complained about Mr. Davis’s cost cutting to Linda Yaccarino, who became X’s chief executive in 2023, and asked her to rein him in, two people with knowledge of the discussions said. He left X soon after.
When Mr. Musk stumped for Mr. Trump in Pennsylvania during last year’s presidential campaign, Mr. Davis relocated to hotels in Philadelphia and Pittsburgh to oversee a super PAC that Mr. Musk had backed, three people said. Mr. Davis helped conceive a $47-a-head petition that Mr. Musk promoted to turn out Trump voters, and cited his Twitter cost cutting as a way of doing things cheaply at the super PAC.
After Mr. Trump won the election, Mr. Davis joined a transition “landing team” and interviewed candidates for Mr. Musk’s efficiency commission. He also met with agencies that employed engineers to assess the technical talent that DOGE might tap, three government officials said. Mr. Musk included Mr. Davis in recruiting pitches to potential government hires, according to an internal email seen by The New York Times.
After Mr. Trump’s inauguration, Mr. Davis pushed administration officials to let him email all government employees at once, two people with knowledge of his efforts said. That led to a January email blast known as the “Fork in the Road,” which included a governmentwide resignation offer.
When leaks about the resignation offer circulated in the media, Mr. Davis rebuked officials for not controlling their staffs and accused them of embarrassing Mr. Musk, two people said.
Mr. Davis pushes for Mr. Musk’s priorities daily with Mr. Trump’s advisers, two people with knowledge of the conversations said. He has alerted administration officials to diversity, equity and inclusion programs that are targeted for cuts and individuals to be removed from government boards.
Mr. Davis, who can be blunt and undiplomatic, especially in late-night texts, has also clashed with some of Mr. Trump’s staff. He and his colleagues upset some White House advisers with the way DOGE tried to place some of their recruits at the Pentagon, three people said.
Throughout, Mr. Davis has studiously avoided attention. Mr. Musk and the White House have not mentioned him. In Washington, Mr. Davis mostly avoided having his picture taken until this month, when he spoke at the DOGE Caucus, a House of Representatives group that works with the cost-cutting task force.
“Wrapped a great meeting with @elonmusk and Steve Davis on their goals for the @DOGE,” Representative Aaron Bean, Republican of Florida, posted on X. The message included a photo 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 research.