GEOFF BENNETT: President Trump has tasked Elon Musk with an enormous job, to search across the federal government and root out inefficiencies and waste.

But Musk's initial, often chaotic infiltration of various government departments has sparked alarm.

It's also put the tech entrepreneur at center stage of the conservative movement, appearing today in front of an audience at CPAC, wielding a chain saw he said he'd used to slash the federal bureaucracy.

William Brangham looks at the history of the man at the center of this effort.

ELON MUSK, Department of Government Efficiency: If the bureaucracy is in charge, then what meaning does democracy actually have?

WILLIAM BRANGHAM: Elon Musk, the richest man in the world, now standing in the most powerful office in the world.

ELON MUSK: The people voted for major government reform.

There should be no doubt about that.

WILLIAM BRANGHAM: But how did this visionary tech leader, a man who once championed clean energy to save the planet and remained politically neutral for much of his career, end up working with President Donald Trump to dramatically scale back the size of the federal government?

TIM HIGGINS, The Wall Street Journal: Very rarely do you see a business leader essentially camping out in the White House, trying to influence government spending, influence government regulations the way Elon Musk is doing.

WILLIAM BRANGHAM: The Wall Street Journal's Tim Higgins wrote a book on Musk and Tesla called "Power Play."

TIM HIGGINS: There's also this kind of "prove the world wrong" mentality.

He's got a huge chip on his shoulder.

For so long, he's been told that what he was doing wasn't possible, that he was crazy, that he couldn't do it.

And you -- when you talk to him, you realize he likes proving people wrong.

KATE CONGER, The New York Times: He tends to think in terms of missions for himself.

So, those usually revolve around making a big impact for humanity.

WILLIAM BRANGHAM: Kate Conger covers Musk for The New York Times and co-authored the book "Character Limit" about Musk's takeover of Twitter, which he renamed X. KATE CONGER: You see this with SpaceX, where he's trying to extend the life of humanity by establishing colonies on Mars, with Tesla, where he's trying to cut back on E.V.

emissions and save the planet.

And with X, too, he has given himself this mission of what he sees as protecting and saving online free speech.

And his approach to the Trump administration is the same.

He views this as an opportunity to save America and save democracy.

WILLIAM BRANGHAM: Musk grew up in a wealthy family in 1970s South Africa, then still in the midst of its racist apartheid regime.

Walter Isaacson, who wrote a biography of Musk, told Amna Nawaz back in 2023 that Musk had a difficult childhood, struggling with autism spectrum disorder, being repeatedly bullied, and dealing with an allegedly emotionally abusive father.

WALTER ISAACSON, Author: Those demons, the dark things about being bullied as a kid, having psychological problems with his father, turn into drives too, drives that get him to be the only person who can get astronauts into orbit from the United States or reuse rockets and land them or bring us into the era of electric vehicles.

But it also makes him a dark and mercurial character and sometimes a crazed character at times.

WILLIAM BRANGHAM: Musk moved to the U.S. for college, where he studied physics and economics, but building Web-based products, including an online banking service, is what earned him his first real fortune.

It was around this time that Elon Musk turned his sights to two very different fields, the nascent electric car industry and the decades-old competition to conquer space.

Musk quickly became a groundbreaking pioneer in both.

MAN: And launch of the SpaceX Falcon 9 rocket.

WILLIAM BRANGHAM: Musk founded the rocket company SpaceX in 2002 and quickly became a key partner with NASA on both manned and unmanned spaceflights.

Musk invested in Tesla, then a fledgling electric car company, and would eventually become its CEO.

ELON MUSK: An electric car can be the best car in the world.

WILLIAM BRANGHAM: In a remarkably short span, Tesla became the world's most valuable auto company.

TIM HIGGINS: Time and time again, as you look out through kind of his career arc, it's his ability to build excitement around his vision that tends to help him win the day.

It's tapping into this kind of primal idea, this excitement that people have about what is possible.

WILLIAM BRANGHAM: Another of his ventures is Starlink, a satellite Internet provider that's used in over 100 countries and has large U.S. government contracts.

As these various businesses have grown, so has his net worth.

In 2021, he became the world's richest man.

And yet, despite Musk's power, he has spent most of his career avoiding politics.

ELON MUSK: And I'm sort of moderate, sort of half Republican, half Democrat, if you will.

But I'm somewhere in the middle.

I guess I'm sort of socially liberal and fiscally conservative.

WILLIAM BRANGHAM: During the first Trump administration, Musk quit a presidential advisory board in protest after Trump withdrew from the Paris climate accord.

But, during the pandemic, his politics began a rightward turn.

He hated being ordered to lock down his Tesla plants in California.

KATE CONGER: He was also, at the time, going through some things in his personal life.

He had a child who was coming out as trans and beginning a gender transition.

WILLIAM BRANGHAM: Musk often blamed his child's transition on so-called woke ideology.

ELON MUSK: They call it dead-naming for a reason.

MAN: Yes, I'm... ELON MUSK: So the reason it's called dead-naming is because your son is dead, killed by the woke mind virus.

WILLIAM BRANGHAM: Additionally, in 2021, Musk was excluded from a Biden administration summit on electric cars because Tesla had blocked unionization at its facilities.

KATE CONGER: That's something that Musk has typically resisted in his factories.

So Tesla was excluded, and that really bothered Musk.

WILLIAM BRANGHAM: Over the years, Musk spent increasing amounts of time on Twitter, shooting out messages at all hours of the day and night, everything from vulgar jokes to business updates to memes that critics called racist and sexist, even his intention to buy the platform outright.

He first tried to walk that back, but then purchased Twitter for $44 billion in 2022, promising to create a digital town square, but quickly taking actions that echo his work today in Washington.

KATE CONGER: Musk's takeover of Twitter was really chaotic, I think by any measure.

He came into the company and very quickly wanted to slash its budget, and that meant getting rid of everything from a large number of workers, to getting rid of real estate, to firing the janitorial staff who were cleaning the offices.

Really, no item in Twitter's budget went untouched.

WILLIAM BRANGHAM: Musk changed the platform's policies on hate speech, and when analysts claimed that vitriol then flourished on the renamed X, advertisers balked and the company's value slid.

In characteristic fashion, Musk had no time for his critics.

ELON MUSK: If somebody's going to try to blackmail me with advertising, blackmail me with money, go (EXPLETIVE) yourself.

Go (EXPLETIVE) yourself.

MAN: But... ELON MUSK: Is that clear?

WILLIAM BRANGHAM: Meanwhile, colleagues and board members at his companies reported that they were increasingly concerned about Musk's mental health and drug use, specifically the drug ketamine, which Musk says he's prescribed to treat depressive episodes.

He began leaning even further into politics, backing Republican candidates during the 2022 midterms and labeling Democrats the party of division and hate.

And he extremist, hard right views on X, endorsing the so-called Great Replacement Theory that argues Democrats want open borders to replace white voters, and he elevated antisemitic conspiracy theories.

Though he initially didn't support Trump's reelection, saying he was too old to return to the White House, after last year's assassination attempt, he changed his mind.

ELON MUSK: The true test of someone's character is how they behave under fire.

And we had one president who couldn't climb a flight of stairs, and another who was fist-pumping after getting shot.

WILLIAM BRANGHAM: Musk formed a super PAC to support Trump's bid, donating more than $200 million of his own money.

ELON MUSK: This election, I think, is going to decide the fate of America, and along with the fate of America, the fate of Western civilization.

WILLIAM BRANGHAM: Trump, in turn, embraced Musk on the trail and promised a role for him in a second administration.

DONALD TRUMP, President of the United States: I will create a government efficiency commission tasked with conducting a complete financial and performance audit of the entire federal government and making recommendations for drastic reforms.

WILLIAM BRANGHAM: Following Trump's win, Musk continued to turn heads by supporting a far right political party in Germany that's been accused of resurrecting Nazi era ideology and speaking to one of its rallies.

Now, as Musk leads this effort to scrutinize and cut federal agencies from within, his own companies retain massive multibillion-dollar government contracts.

Musk has resisted any financial disclosures and claims there's no conflict with his cost-cutting efforts.

And while there are numerous court challenges to his efforts, Musk continues to enjoy the full support of President Trump.

DONALD TRUMP: The team we have is really unbelievable.

But those executive orders, I sign them, and now they get passed on to him and his group and other people, and they're all getting done.

We're getting them done.

WILLIAM BRANGHAM: For the "PBS News Hour," I'm William Brangham.