The social media company pulled out a corporate takeover playbook as it negotiated a sale to Musk.

Mr. Musk did the opposite.

Mr. Musk told an associate that he had no plan for how to finance or manage the micro-blogging site. The $44 billion deal was pushed through by a small inner circle, including the head of his family office and his personal lawyer. Mr. Musk pressured the company with a string of impulsive and mischievous statements.

Tech billionaires such as Bill Gates, Jeff Bezos and Larry Page use a corporate machinery of lawyers, communications professionals and different advisers to make long-term plans. Mr. Musk is different from all of them.

Interviews with more than 30 current and former employees, investors, and others who have worked with the mogul show that he acts on whim, fancy, and the certainty that he is 100 percent right. While Mr. Musk has successfully bet on electric cars, space travel, and artificial intelligence, he often goes it alone in the biggest moments and relies on his own counsel.

Mr. Musk has built a world of about 10 people who mostly agree with him and carry out his bidding. Kimbal Musk, Mr. Birchall, Mr. Spiro, and various chiefs of staff are related to him. Mr. Musk keeps creating new companies so that he remains in charge. His trusted lieutenants work across his businesses.

Alex Spiro, Mr. Musk’s personal lawyer.Credit...Apu Gomes/Agence France-Presse — Getty Images

Once Mr. Musk has identified each company's key project, he takes over to ensure that his vision is met. His brilliance has spawned the world's most valuable automaker and an innovative rocket company, and it has earned the respect and fear of his engineers.

Hewing to his own thinking and relying on his small crew have enabled Mr. Musk to call the shots, turning him into a Howard Hughes-like figure of the modern age.

Tim Draper, a venture capitalist who backed Mr. Musk, said that Mr. Musk works in a way that only the most confident leaders do.

Mr. Musk said that he acted on impulse. He said it was a lesson he learned after founding his first start-up, Zip2.

He said that he didn't have a business plan. I didn't bother with business plans after that because they are always wrong.

Implications for what Mr. Musk might do with the social media site are related to how he operates. The billionaire is set to take ownership of the San Francisco company in the next six months and has been in an uproar over the deal. As the takeover drama played out, its new proprietor publicly criticized the platform, took aim at senior Twitter executives who oversee speech rules on the service and needled Representative Alexandria Ocasio-Cortez and Mr. Gates on the site.

Kimbal Musk, Mr. Musk’s younger brother.Credit...Ryan David Brown for The New York Times

We don't know what direction this company will go in after Mr. Musk takes over.

Mr. Musk is not ignorant of the chaos that he leaves behind. Mr. Musk referred to himself as an idiot in an email about the defamation case. In a deposition over a failed attempt to take the company private, he ruefully said, "If I had a hindsight machine, that would be really great."

As a child, Mr. Musk was interested in computers and programming languages. After graduating with degrees in economics and physics from the University of Pennsylvania in 1992, he moved to the United States to enroll in a PhD program in physics.

Mr. Musk dropped out of college to pursue a career in business. His first start-up was a travel guide service called Zip2. Zip2 was bought by Compaq for $300 million.

In 1999, Mr. Musk helped found X.com, an online payments company. Even if his employees weren't prepared, he began making business declarations.

ImagePeter Thiel, left, and Mr. Musk in 2000. They worked together on the company that would become PayPal before Mr. Thiel helped oust Mr. Musk.
Peter Thiel, left, and Mr. Musk in 2000. They worked together on the company that would become PayPal before Mr. Thiel helped oust Mr. Musk.Credit...Paul Sakuma/Associated Press

In a live television appearance, Mr. Musk said the company would guarantee transactions on all eBay auctions. A person who worked with him said that it was the first time his engineers had heard about the feature. The person said that they had to race to make the feature a reality.

Mr. Musk was ousted by the X.com board in 2000. It was a difficult exit for Mr. Musk, as he embraced the idea that he alone should be in charge of future ventures.

Mr. Musk made sure he could exert his will at each company he built. He poured more than $100 million of his own money into the firm in its early years. Mr. Musk has a 16 percent stake in the company and has a friendly board with his brother and friend.

In 2007, he told Inc. Magazine that it was okay to have your eggs in one basket.

Kimbal Musk and Mr. Gracias, who left the board of the company last year, declined to comment.

Mr. Musk is associated with at least a dozen companies, including public ones, private ones, and holding companies, such as Wyoming Steel, which he uses to manage real estate. His net worth is $250 billion.

Mr. Musk was able to deploy associates across many of his endeavors.

Mary Beth Brown was hired in 2002 to be Mr. Musk's executive assistant. She became a kind of chief of staff, handling media requests and some financial matters, as well as helping to manage Mr. Musk's personal life.

Mr. Musk hired Gwynne Shotwell as a seventh employee. Ms. Shotwell is one of Mr. Musk's longest-serving employees.

Ms. Shotwell talked about how she managed Mr. Musk.

Gwynne Shotwell, SpaceX’s president and chief operating officer.Credit...Patrick T. Fallon/Bloomberg

It's impossible to stop and not immediately blurt out when Elon says something. I don't know how to do that. You find a way to get that done.

Ms. Brown could not be reached for comment. Ms. Shotwell didn't reply to the request for comment.

Mr. Musk started treating his companies as a single organization.

In 2015, he and a group of researchers founded OpenAI, a lab developing artificial intelligence to benefit humanity. Two people with knowledge of the work said that Mr. Musk enlisted several OpenAI researchers to help with the project. He later appointed a researcher from OpenAI as a senior director of artificial intelligence.

Neuralink was founded seven months after Mr. Musk started OpenAI. The building in San Francisco's Mission district is where OpenAI and Neuralink are located. The companies held group lunches with the idea that they would work together.

Jared Birchall, the head of Mr. Musk’s family office.Credit...Patrick T. Fallon/Bloomberg

Mr. Musk brought in Mr. Birchall as the head of his family office. Mr. Birchall was listed as the chief executive, chief financial officer and president of Neuralink. His name appeared in correspondence with San Francisco city officials when the company sought permission to do research on animals.

Mr. Birchall is Mr. Musk's personal fixer, and he is also the founder of Pravda Corp., a company that is registered for Mr. Musk. Mr. Birchall did not reply to questions.

Mr. Musk's business empire was growing. The billionaire sometimes showed an ugly side of his management style.

The fatal crash of Joshua Brown, who was using the autopilot feature in his car, happened in June of 2016 The general counsel for the National Highway Traffic Safety Administration explained in a call that it was opening a formal investigation into autopilot.

Four people with knowledge of the incident said that Mr. Musk erupted. If the investigation went forward, he threatened to file a lawsuit. The agency proceeded with the investigation after Mr. Musk backed down.

Mr. Musk's seat-of-the-pants decisions made his employees angry. He traveled to Guadalajara, Mexico, in September of 2016 to make an announcement about the plan to send humans to Mars. Some of his executives, who had to brief NASA and other partners, had no idea what he was going to say.

In 2018, Mr. Musk talked to the news media with the SpaceX Falcon Heavy rocket behind him in Cape Canaveral, Fla. Credit...Todd Anderson for The New York Times

Mr. Musk said there was a high chance that people would die on the first trip to Mars.

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Engineers working on autopilot were taken aback by Mr. Musk's announcement of a new version of the system. They were surprised when their boss said that a more advanced version of autopilot, called Full Self Driving, was six months away. Full Self Driving is not widely available.

Mr. Musk's solo, impetuous style came back to bite him.

Mr. Musk wanted to increase production of the company's Model 3 sedan. The executive in charge of manufacturing was fired and the entire assembly line of the company was changed by himself. He usually slept in a conference room.

Mr. Musk told The New York Times that there were times when he didn't leave the factory for three or four days. The company eventually said it had hit its production targets.

A person who visited the factory said that Mr. Musk was sometimes joined by Sam Teller, who had a sleeping bag. Mr. Teller and Mr. Zilis both held titles at multiple Musk-run companies.

Mr. Teller didn't respond to requests for comment. Ms. Zilis is still employed by the billionaire.

Sam Teller, who was one of Mr. Musk’s trusted lieutenants.Credit...Alexandra Wyman/WireImage via Getty Images

Mr. Musk decided that he was tired of being a part of the public market. He sent an email to the company's board with the subject line: "Offer to TakeTesla Private for $420." There were few details about how the offer would be funded.

Mr. Musk's inner circle was overjoyed. The messages were included in a court filing.

On August 7, Mr. Musk said he was considering taking the company private for $420. Funding was secured.

James Murdoch, the media mogul who sits on the board of the company, sent a message to Mr. Musk.

Mr. Musk said everything was better with fire.

Mr. Musk's effort failed despite the cheerleading from inside. The funding that he had expected to come in didn't come through. He was sued by shareholders for securities fraud. The SEC charged Mr. Musk with securities fraud.

Shivon Zilis, who oversees special projects for Mr. Musk.Credit...Stephen Lam

The then-chief financial officer said in a deposition that Elon's approach of doing business is minimum level of documentation.

The S.E.C. fined Mr. Musk $20 million. The lawsuit is still going on.

Mr. Musk was involved in a defamation case with a British cave explorer. Mr. Unsworth was critical of Mr. Musk for building a submarine for the Thailand cave rescue. Mr. Musk called Mr. Unsworth a pedo guy, prompting a defamation suit.

According to court documents and depositions, Mr. Birchall hired a private investigator to dig up information on Mr. Unsworth because he had an instinct to protect his boss. Mr. Musk sent the information to the reporter. The private eye was a fraud.

One of the dumbest things Mr. Musk has ever done is to send information to a reporter.

Jay-Z's lawyer, Mr. Spiro, was hired by Mr. Musk to lead his defense. Mr. Spiro argued that Mr. Musk had made a joke of his client. The two have been in touch.

Throughout the ups and downs, Mr. Musk had one constant.

He uses his more than 90 million followers to shoot barbs at the short sellers ofTesla and other companies, as well as sharing meme and ruminating on the epidemic, politics and Doge coin. He eliminated the communications department in 2020 because he felt he could go directly to fans and customers on social media, according to three former employees.

Mr. Musk bought it because of his love for the company. According to financial documents, he had Mr. Birchall handle the deal last month. Mr. Spiro spoke to the media. Three new companies were created by Mr. Musk, which were involved in financing theTwitter transaction.

Mr. Musk was in Texas to discuss a new rocket engine with an engineering team. On Wednesday, he wrote, "Let's make maximum fun of it!"

Jack and Lauren were involved in the reporting.