On the day after Doug Burgum became governor of North Dakota in 2016, he addressed questions about what he would do about all of his wealthy investments.

They included extensive real estate developments benefiting from state programs that he was suddenly in a position to oversee. His answer was that he would “manage” his conflicts of interest, but he would not divest from his holdings in the state.

“The issue here is to make sure that I have no conflict of interest relative to many state programs and decisions,” he said at the time in an interview with a local newspaper.

Since then, however, his range of holdings, which include extensive urban real estate development in the state, tens of millions in technology investments as well as oil and gas leases, intersected with his policy decisions as governor, a New York Times review has found.

That is particularly true for extensive development efforts in downtown Fargo that have been the beneficiaries of targeted state and federal tax benefits. But at the time, he did not disclose the specifics of any potential conflicts or how he managed them.

Now, as Donald J. Trump’s pick for secretary of the interior, Mr. Burgum could face questions about how he plans to avoid conflicts in leading an agency with vast influence over the use of public lands in ways that reverberate for landholders, energy producers and others.

Rob Lockwood, a spokesman for Mr. Burgum, said in an email to The New York Times: “Everyone who knows Doug Burgum knows that he is a man of outstanding character and ethics who complied with all guidelines as governor.”

Mr. Burgum, whose confirmation hearing is scheduled for Thursday, said in an agreement with the Office of Government Ethics that he would divest from a few holdings that include oil and gas and mineral leases that could pose conflicts.

But he also said he would hold on to other investments that he had been advised might be financially affected by particular matters that could come before the interior secretary. These investments include a range of venture capital funds and some of his Fargo real estate developments, though he will resign from managerial duties in his companies. In those cases, he said, the ethics office had determined that he would be able to recuse himself from decisions that had an impact on those entities or get a waiver.

The Interior Department has long been susceptible to ethical concerns. It has influence over how vast tracts of mineral-rich federal land can be used. During Mr. Trump’s first term, the department became a center of allegations and investigations about conflicts of interest involving high-ranking officials, including the two men who served as its secretary.

Federal law has much stricter disclosure and recusal standards than Mr. Burgum operated under as North Dakota’s governor. It also has criminal prohibitions against officials becoming involved in decisions that could personally benefit themselves or family members.

Mr. Burgum previously disclosed his detailed financial assets for the first time in 2023 as a presidential candidate. An updated version he submitted recently was released by the government ethics office on Wednesday ahead of his hearing, showing a range of assets that could puts his net worth well over $100 million.

While Mr. Burgum was governor, his policies included expanding a state tax program targeted narrowly at real estate development firms like his own that were seeking to revitalize aging downtowns.

His firm, called Kilbourne after his mother’s maiden name, was one of a handful of developers in the state relying in a significant way on such tax breaks and by far the largest in Fargo, according to local officials. He also gave final approval to the zones that benefited from a federal tax credit program, which included areas with his company’s projects in them.

Mr. Burgum was not paid a salary by Kilbourne and “had zero operational authority,” Mr. Lockwood said.

Still, Mr. Burgum continued to have investments in the company’s projects and maintained formal positions in their entities, financial disclosure forms show.

While Mr. Burgum was in office, questions about other ethical choices emerged, including his use of a luxury box at the Super Bowl provided by a regional electricity utility.

After the tickets were reported by The Associated Press, Mr. Burgum said he accepted them to have “quality time” with company executives and he repaid the utility $37,000.

The controversy prompted the governor’s office to enact an ethics policy stating that office officials should “take great care to avoid conflicts of interest or even the perception of a conflict of interest,” including in cases of overseeing policies that involve personal business interests. But the guidelines did not state what actions should be taken when an appearance of a conflict arose.

More enforceable state ethics rules requiring disclosures of potential conflicts of interest did not go into effect until 2022, the result of a 2018 ballot initiative.

Ethics experts in North Dakota and outside the state say that under generally understood norms, Mr. Burgum probably should have made more disclosures about potential conflicts and how he would mitigate them.

“Even a small appearance is enough to trigger an obligation to be open to the public,” said Kedric Payne, a government ethics expert with the Campaign Legal Center.

‘Nobody Really Cared’

In his first State of the State address, in 2017, Mr. Burgum laid out an unusual plan for a state that was one of the most sparsely populated in the country: Go urban.

“It takes safe, healthy cities with vibrant, walkable main streets and downtowns to attract and retain a skilled work force,” he said.

In Mr. Burgum’s vision — built upon his mother’s reverence for historic buildings — North Dakota towns would grow upward rather than outward.

His dream also aligned with his business strategy.

For more than a decade, he had been focusing his development interests in downtown Fargo, eventually becoming one of the state’s biggest urban developers. He also became one of the most reliant on a government tax incentive program called Renaissance Zones.

The program gave state tax incentives for companies that invested in neglected neighborhoods. Mr. Burgum quickly made use of them as well as other similar tax break programs, through acquiring and renovating a turn-of-the-century manufacturing building that was scheduled for demolition, and then turning it over to the local university.

The program allows for state income tax exemption for five years, offering investors in big projects to save up to hundreds of thousands of dollars a year per project in property tax savings.

Twenty Kilbourne projects worth about $300 million have received the Renaissance designation, Jim Gilmour, the city’s director of strategic planning and research, said in an interview. Each of the Kilbourne Renaissance projects was approved individually by a number of city and county entities, with the state’s Commerce Department overseeing the program.

As governor, Mr. Burgum eventually made an expansion of the program a plank in his economic agenda. In his State of the State speech in 2023, he proposed a “Renaissance Zone 2.0.” Among the changes, which were enacted by the Legislature and signed by Mr. Burgum, was a provision to allow for the tax benefits to last an extra three years.

(Kilbourne has not added any new Renaissance Zone projects since then, and Fargo’s county government so far has not agreed to adopt the expansion in benefits.)

Dustin Gawrylow, a longtime Republican critic of the program who unsuccessfully lobbied against the bill, said the perception of a conflict from Mr. Burgum’s status as a top Renaissance developer who could potentially benefit from the expansion was sometimes discussed behind closed doors around the State Capitol.

“It was brought up, but nobody really cared,” Mr. Gawrylow said.

Mr. Lockwood said that “local leaders, the media, and Fargoans are very aware of Doug’s decades-long efforts to revitalize the city.”

Managing Conflicts

While Mr. Burgum was running for governor in 2016, a different state tax break program he used became a subject of discussion on the campaign trail.

Mr. Burgum had founded in 2008 a firm called Arthur Ventures with his nephew, James Burgum, that had invested about $65 million in technology startups up to that point. The firm had taken advantage of a state angel investment tax break program, which provided benefits for certain funds that put money into small startups.

Two funds managed by Arthur Ventures earned investors $800,000 in tax benefits. But the program came under fire from Republican lawmakers for sending a large portion of the investments into out of state startups.

In March 2016, while Mr. Burgum was campaigning, James Burgum testified before the Legislature to try to help save the program that was under attack. The campaign of Doug Burgum’s Republican opponent called him the “poster child” for the problems with the program.

Mr. Lockwood said in his statement to The Times that “job creators being attacked by career-politician opponents for using a law designed to encourage economic investment, innovation and entrepreneurship in North Dakota was a ‘water is wet’ moment.”

Later in the campaign, after Mr. Burgum’s Democratic opponent raised concerns about his ability to manage conflicts of interest, Mr. Burgum said he would “take all the appropriate steps to assure North Dakotans that I’m fully focused on serving them with integrity and transparency.”

After taking office, he explained that meant that he gave up his day-to-day management positions while maintaining his investments under the leadership of others.

But the federal disclosure Mr. Burgum filed to run for president in 2023 revealed that he did not entirely step away. He was listed in various positions ranging from manager and president for various Kilbourne-affiliated limited liability companies and maintained investments of around $15 million to $60 million in several dozen Kilbourne-related entities and funds.

Kilbourne’s managers downplayed his role in the firm, even as they highlighted his affiliation as helping to attract other investors. In an interview with a local publication, Lauris Molbert, Kilbourne’s executive chairman of the board, said the governor’s hefty investments were an important signal to other investors to get on board.

“He personally put his balance sheet to work,” Mr. Molbert said.

A Development Opportunity

In the spring of 2018, a state news release announced that Mr. Burgum had designated 25 neighborhoods in North Dakota to be opportunity zones.

Their designation was part of a new federal program similar to Renaissance Zones but devised to limit federal tax liability in order to help direct investment into struggling neighborhoods.

The idea, Mr. Burgum said, was to “help revitalize our low-income areas in North Dakota.”

Left unsaid, however, was that two of the neighborhoods chosen were ones where his firm owned properties it was hoping to develop. In the years that followed, Kilbourne developed five projects in those areas through two investment funds that offered the tax breaks, with Mr. Burgum’s stake valued between $2 million and $10 million, according to his 2023 financial disclosure.

The structure for the opportunity zones was enacted under the Trump administration, and governors were given leeway in selecting the zones as long as they met certain criteria.

Under the system set up in North Dakota, the city and county of Fargo applied to the state’s Commerce Department for opportunity zone status for 11 areas, including the two containing the Kilbourne properties. Of those, Mr. Burgum designated the two with his properties and three others in the region.

Brett Theodos, a senior fellow at the Urban Institute who has studied the federal opportunity zone program, said he had never heard of such a prominent official tasked with designating the areas having a stake in the zones selected.

“A lot of the country qualified, so there were a lot of options for governors to choose from,” he said. “The whole trust-us approach is problematic.”

Tim Mahoney, Fargo’s mayor, said in an interview that initially he had concerns about whether Kilbourne might get favored in its extensive dealings with the city, but he has concluded that the treatment was aboveboard.

The city relies extensively on the approval of state loans and other sources of funding that are under the governor’s purview.

Mr. Mahoney said he had not spoken to Mr. Burgum directly about any of Kilbourne’s business. But, he said, the governor had met with the planning department and pressured him and other city officials repeatedly to make downtown development a major priority, arguing that added properties build a tax base that supports schools, water, the police and city streets.

That fits with Mr. Burgum’s general evangelism for urbanism — and with where he has invested his money.

“The governor was very clear on what his bias was,” Mr. Mahoney said. “His bias is downtown places will make more in taxes for everybody.”

Russ Buettner contributed reporting.