After Donald Trump asked the oil industry to contribute $1 billion to his presidential campaign in April, oil baron Harold Hamm immediately started working the phones.

Hamm, the billionaire founder of Continental Resources, called other oil executives and encouraged them to attend fundraisers and open their wallets, according to people with knowledge of the outreach, who, like others interviewed for this article,spoke on the condition of anonymity to describe private discussions.

“We’ve got to do this because it’s the most important election in our lifetime,” Hamm said as he made calls after the April dinner at Trump’s Mar-a-Lago Club, where the former president made the audacious fundraising ask, according to an associate.

Another person familiar with the matter said Hamm railed against President Joe Biden’s energy policies and argued that even if donors didn’t love Trump, it made sense to support the former president. In recent months, Hamm has also orchestrated some introductions between oil executives and Trump, and Trump has now “called almost everyone in the sector,” said a person involved in the industry.

Hamm, a sharecropper’s son who rose to become one of the world’s richest men, would seem to be an unlikely power broker. He doesn’t travel with an entourage and doesn’t keep a high profile. Yet hehas emerged as a central figure in cajoling the oil industry to finance Trump’s reelection bid, and in communicating to the ex-president what the oil industry wants to improve its fortunes in a second Trump term.

His message appears to be resonating with some of the country’s wealthiest oil magnates, who are banking on Trump’s promises to reverse dozens of Biden’s environmental rules and policies.

The money has been flowing in. The oil and gas industry has contributed more than $20.3 million to the Trump campaign, pro-Trump super PACs and the Republican National Committee in the 2024 cycle, according to data from OpenSecrets. Trump is expected to do more oil and gas events later this year, aides say.

The industry has much at stake in the election. Although the United States last year produced more oil than it ever has, Kamala Harris could blunt that trajectory if she were to defeat Trump and replace Biden. As attorney general in California, Harris prosecuted oil companies for leaks from pipelines and storage tanks, and even sued the Obama administration for allowing fracking off California’s Pacific coast — reasons that Hamm and other fossil fuel executives worry about what the next four years could look like.

Hamm is working “incredibly hard to raise as much money as he can from the energy sector,” said a Trump campaign aide. “We’ve gotten max-out checks from people we’ve never gotten a dollar from before.”

Some of the Trump campaign’s top individual donors include Texas oil billionaires Jeffery Hildebrand and George Bishop and pipeline mogul Kelcy Warren. Since March, they and their spouses have given at least $9.9 million, according to Federal Election Commission filings.

Spokespeople for the companies overseen by Hildebrand, Bishop and Warren did not respond to requests for comment.

Hamm has a wish list of policy changes in a second Trump term that would pad his profits and those of other oil executives. At the top of the list: opening up more federal lands to drilling, easing the Endangered Species Act and curbing numerous regulations at the Environmental Protection Agency, according to people familiar with his demands.

Hamm has encouraged other oil executives to share their policy priorities with Trump as well. Trump and Hamm have also bonded over their shared dislike of wind energy, according to people familiar with the matter.

In addition, Hamm wants close ties with a potential second Trump administration, say people who have interacted with him. In the first Trump term, former administration officials said, his calls were always immediately returned, and he enjoyed a close relationship with top Cabinet officials.

“Harold Hamm is back there — he’s my original oil guy that taught me so much about oil,” Trump said at a fundraiser in Houston in May, according to donors who attended. “This guy knows more about oil and gas. … That’s all he knows. That’s the problem. He’s so boring to be with, you know, because all he wants to talk about is oil and gas. No, we love Harold. He’s a piece of work. I’ll tell you that.”

At another event, Trump said: “Harold can just stick his finger in the ground, and oil will come up.”

Mike Cantrell, a former Continental Resources executive, said that if anyone could eventually raise $1 billion from the oil industry, it’s Hamm. “It’s limitless what he can raise, if he wants to do it,” he said.

Sen. Kevin Cramer (R-N.D.), who relied on Hamm’s fundraising prowess to boost his 2018 Senate bid, said that Hamm has “a very active Rolodex” of oil donors. “Harold does the leg work,” he said. “He has a lobbyist or a government affairs person … but he makes the phone calls.”

At the Mar-a-Lago dinner in April, Trump told oil executives that raising $1 billion for his reelection bid would be a “deal” because of the taxation and regulation they could avoid. Hamm spoke little at the dinner, attendees said. Cramer agreed.

“When you see the type of money that liberal billionaires are putting in the presidential races these days, it should be easy for the oil and gas industry, especially considering the dramatic difference in regulatory policy decisions between the two parties, the two campaigns,” Cramer said.

Hamm did not respond to multiple requests for comment. Asked detailed questions about Hamm, a Trump spokeswoman sent a statement that did not mention him.

“President Trump is proud to be supported by people who share his vision of American energy dominance to protect our national security and bring down the cost of living for all Americans,” Karoline Leavitt, the spokeswoman, said.

Getting back on the ‘Trump train’

Hamm has wavered in his support for Trump, initially backing Florida Gov. Ron DeSantis and former South Carolina governor Nikki Haley in the Republican presidential primary. But, like many Republicans who were once critical of Trump, he has come around.

The two came to know each other in 2012, when Hamm dropped by Trump Tower to say hello, and Trump took him down to the gift shop and gave him free ties. Trump later sent more free ties after seeing Hamm wear one of them on the cover of Forbes magazine.

Throughout Trump’s first term in office, Hamm was a reliable supporter of the administration and regularly spoke to the president. In early 2020, he lobbied Trump to help persuade Saudi Arabia and Russia to end a price war that had driven down the price of oil below $0 a barrel, causing Hamm to lose $3 billion in just a few days, people familiar with his meetings said.

The effort appeared to pay off. In April 2020, under pressure from Trump, members of OPEC, Russia and other oil-producing nations agreed to the largest production cuts ever negotiated — nearly 10 million barrels a day — as oil demand collapsed during the pandemic.

After the Trump presidency, however, Hamm repeatedly met with DeSantis and was tempted by his candidacy, according to people with direct knowledge of the discussions. He gave DeSantis an extensive briefing on oil and energy policy and even came with a full plan, a person familiar with the pitch said. He praised North Dakota Gov. Doug Burgum (R) for his policies on fracking and sought to secure assurances from DeSantis that he would be friendly to the oil and gas industry, the person said.

Last summer, Hamm publicly called for Trump to drop out of the race and donated to the presidential campaigns of DeSantis and Haley, the former U.N. ambassador. Privately, he complained to friends that Trump had not responded to his request for a pardon for an associate near the end of his term, and he was frustrated with Trump’s behavior at times, Hamm associates say.

But eventually, Hamm changed his mind, saying he just wanted Biden out of office and Trump was the clear GOP front-runner. “We have to get back on the Trump train,” he told one associate last year.

Hamm had dinner with Trump in Bedminster, N.J., in July 2023, just before Hamm’s book came out, according to people familiar with the meeting. In the book, titled “Game Changer: Our 50-Year Mission to Secure America’s Energy Independence,” Hamm described his fractured friendship with the former president.

“I get asked a lot about my support for former President Trump running again,” he wrote. “Although many of his policies were sound and helped our nation prosper, he simply did not stand with many of those who stood with him. My strong belief is there are better qualified candidates who can unite the country in the next election to lead America back to an era of energy abundance.”

Yet after the book publication, Hamm continued to meet with Trump. In October 2023, he showed up at Mar-a-Lago in Palm Beach, Fla., brought a $200,000 check for a pro-Trump super PAC, and attended a private meeting with Trump and an intimate fundraiser with the former president, according to three people familiar with the matter.

This spring, Hamm had dinner with the former president during his New York hush money trial. He also lobbied Trump and his advisers to choose Burgum as a vice-presidential pick, two people with knowledge of his conversations said. The two men have deep business and personal ties: Continental Resources is the largest oil and gas leaseholder in North Dakota, and Burgum wrote a gushing review for the jacket of Hamm’s book.

Burgum declined an interview request about Hamm.

After Trump picked Sen. JD Vance (R-Ohio) as his running mate instead of Burgum, Hamm co-hosted a fundraiser for Vance in Oklahoma City last month. Tickets for the event started at $5,000 per person, while a picture with Vance cost $15,000 and a seat on the host committee cost $100,000, according to an invitation seen by The Washington Post.

Cantrell, the former Continental Resources executive, said Hamm’s initial support for other Republican presidential contenders “created a situation [with Trump] that needed to be mended. And it appears it has been.”

A rags-to-riches story

The youngest of 13 children of Oklahoma sharecroppers, Hamm grew up in a house without electricity or running water. He often skipped school to pick cotton.

Today, Hamm is one of the wealthiest people on the planet, but he still prefers a relatively modest lifestyle, friends and others in the industry say. He would rather drive himself around in a used car than hire a chauffeur, and he would rather carry his own luggage at hotels, according to people who have known him for many years. He is not the most loquacious person nor does he spend much time making jokes, associates say.

“I’ve been in restaurants with him where no one in the restaurant knew he was one of the world’s richest men,” said a longtime associate. “He doesn’t like to ask for special treatment or say, ‘I’m Harold Hamm; don’t you know who I am?’”

While Continental Resources has a lobbyist — Blu Hulsey has handled government affairs for the company since 2010 — Hamm prefers to meet with elected officials himself. In 2015, when Congress was about to lift the ban on U.S. crude oil exports, “there was every company’s lobbyist and Harold” on Capitol Hill, said Cramer, who was a House lawmaker at the time.

Hamm visits Washington multiple times a year, associates say, but won’t join associations of oil companies because he can’t have total control. Instead, he has created his own group called the Domestic Energy Producers Alliance, which enjoyed access to senior officials during the Trump administration. “I’m not a joiner,” he has said privately, a person close to him said.

Hamm’s wealth and influence mean he can have lunch with almost any Republican senator, and he has at times convened large groups of prominent politicians to talk with him about gas and energy, say people familiar with the gatherings.

An avid pilot, Hamm ownsa private jet and also has a ranch in Missouri. A Type 2 diabetic, he has donated $10 million from his foundation to support the OU Health Harold Hamm Diabetes Center.

In 2014, Hamm was ordered to pay nearly $1 billion in a divorce settlement with his ex-wife, Sue Ann Hamm, court filings show. Trump has repeatedly mocked Hamm for the large divorce settlement at fundraisers, saying he couldn’t believe someone as smart as Hamm had to pay $1 billion. Hamm has usually kept a straight face and not responded to that line, while others in the room have laughed, according to donors.