As his second term as governor of New Jersey drew to a close in 2017, Chris Christie was characteristically blunt about his plans.

“I want to have fun, and I want to make money,” he told The New York Times in an interview.

Mr. Christie wasted no time. On his first day out of office, he saw Bruce Springsteen on Broadway. On his second, he met with executives of DraftKings, a fantasy sports behemoth that stood to benefit enormously from the Christie administration’s support for legalizing sports betting. The company later put the former governor on retainer to advise and influence state officials.

Over the past six years, Mr. Christie has repeatedly capitalized, for personal gain, on the connections he made as one of the best-known governors in the country.

He started a federal lobbying and consulting firm called Christie 55 Solutions, joined a multimillion-dollar real estate venture with a donor, landed a contract with ABC News, represented an international fugitive and sat on corporate boards, including that of his beloved New York Mets, the tortured baseball franchise run by his friend and megadonor, the billionaire Steve Cohen.

And in 2018, the Christies bought a multimillion-dollar shorefront home in Bay Head, one of the more exclusive towns on the Jersey Shore. Their neighbors included, at one point, members of Bon Jovi.

The business of being Chris Christie has received only sporadic attention since he left public office. But his latest enterprise — a presidential campaign bent on taking down former President Donald J. Trump, a man he once endorsed and advised — has cast a new light on his success.

A close review of corporate and government records as well as interviews with more than 30 people familiar with his lobbying and consulting work shows Mr. Christie has profited from his relationship to the man he now wants to defeat, as well as from the political profile he gained in eight years as New Jersey’s governor.

Mr. Christie has made millions from interests wanting to leverage his political ties, including pharmaceutical, medical and sports betting companies, like DraftKings — whose hiring of Mr. Christie has not been previously reported. Some had business with the state when Mr. Christie was governor, and saw him as a reliable advocate for their bottom line, while others were interested in tapping into his close association with Mr. Trump and the Trump administration.

Christie 55 Solutions earned roughly $1.3 million in federal lobbying fees from April 2020 to April 2021, according to federal records. The firm also earned more than $800,000 in consulting fees from Pacira Biosciences, a pharmaceutical company with a significant presence in New Jersey. And he has earned around $400,000 a year for his work as a contributor to ABC News, according to a person familiar with the contract.

Before he signed with ABC, multiple networks were interested in and were competing for Mr. Christie, another person familiar with the contract said. ABC later suspended its relationship with Mr. Christie before he began his campaign.

The total value of Mr. Christie’s financial ventures is difficult to tabulate; much of his work involves corporate consulting, contracts that are not generally made public. Mr. Christie, who announced his bid in early June, has not yet been required to file a personal financial disclosure, a requirement for all federal candidates.

Mr. Christie’s campaign declined both to comment on his finances and to disclose his post-governor clients and contracts.

Former public officials from both parties regularly turn to political donors and corporate allies to make money. Former President Barack Obama earned $400,000 in a single speech from a Wall Street firm months after leaving office and later signed a production deal with Netflix, whose founder, Reed Hastings, is a major Democratic donor.

No modern president comes close to Mr. Trump’s voluminous record of conflicts of interest, allegations of self-dealing and post-presidential deal-making that marked the Trump administration and its afterlife. His entanglements have spawned continued interest on the part of ethics experts, watchdog groups and federal prosecutors, who have issued subpoenas for information about his business dealings in foreign countries during his time in the White House.

“The grift from this family is breathtaking,” Mr. Christie said at a recent town hall on CNN.

While Mr. Christie’s own business ties don’t match Mr. Trump’s, they may test how far one more norm has been eroded in the Trump era: Registering as a lobbyist — a card-carrying member of the so-called swamp — has long been viewed as tantamount to retiring from electoral politics.

Ambitious politicians typically tried to put distance between the “public office and the private interests they’re serving,” said Virginia Canter, the chief ethics counsel at the Citizens for Responsibility and Ethics in Washington, a nonpartisan watchdog group.

“But if he’s got all of these other adjacent interests,” Ms. Canter said of Mr. Christie, “how impartial can you be?”

Retaining Mr. Christie was a natural move for DraftKings. As governor, he had been a leading force in the push to overturn the federal law that barred sports betting in most states. In 2018, when the Supreme Court decision in the case initially known as Christie vs. National Collegiate Athletic Association allowed states to legalize sports gambling, the industry rushed to push laws in states that would allow them to cash in on a new market.

Weeks after the court’s ruling, Mr. Christie was the keynote speaker at a conference a gambling industry group hosted for state legislators in New Orleans, where he criticized sports leagues that had opposed expanding gambling.

At the time, Mr. Christie was a consultant for Scientific Games, a lottery company that was part of a consortium that had won big when he privatized the New Jersey state lottery operations in 2013.

The company was now seeking Mr. Christie’s advice on expanding into sports betting. Mr. Christie was paid more than $30,000 a month by Scientific Games, according to a person with knowledge of the arrangement who requested anonymity because the person was not authorized to discuss the contract.

DraftKings also put Mr. Christie on a monthly retainer and then sent him to speak to state legislators, although he did not register as a state lobbyist.

Mr. Christie initially had broad appeal. His blue-state Republicanism made him popular with moderate lawmakers in the Northeast and Midwest, and his ties to then-President Trump gave him credibility with more right-wing legislators.

“Having the George Washington of legalized gaming in the U.S. was obviously something we thought would be helpful,” said Jeremy Kudon, who worked for DraftKings and a rival, FanDuel, on joint lobbying efforts at the time and now runs a gambling industry trade association. “And his relationship with Trump we thought would be helpful.”

But in late 2020, just as the sports gambling industry focused its lobbying efforts on conservative Southern states, Mr. Christie broke with Mr. Trump over the president’s false claims of a stolen election — and DraftKings stopped deploying him.

A spokesman for the company declined to comment.

Mr. Christie has also worked closely with — and for — the pharmaceutical industry, one of the biggest economic drivers in his state.

Just months after leaving office, Mr. Christie was tapped by Mr. Trump to lead the President’s Commission on Opioids, giving him a prominent national post on an issue he had made a major focus of his second term as governor.

Among the industry executives the commission brought in to testify was David Stack, the chief executive of Pacira Biosciences. Mr. Stack pressed for a change in Medicare and Medicaid reimbursement policies, arguing, along with some policy experts, that the programs created incentives for doctors to prescribe opioids instead of non-opioid painkillers and other treatments that are less addictive.

The commission included Mr. Stack’s suggestions in its final report and in 2018, the Centers for Medicare and Medicaid Services changed their policies for non-opioid treatments for pain, citing the recommendation from the Christie-led commission.

The change benefited just one drug on the market at the time: Exparel, made by Pacira.

That same year in 2018, Pacira paid $481,000 to Christie 55 Solutions for consulting work. In 2019, Pacira put Mr. Christie on its board and paid his firm $320,000, according to filings with the Securities and Exchange Commission. The reports did not offer any further details, and the company did not respond to questions about the payments.

As of June 2022, Mr. Christie owned 3,486 Pacira Biosciences shares worth $207,034.

Mr. Christie has said he was not employed by Pacira while serving on the opioids commission.

Sara Marino, a spokeswoman for the company, said Mr. Christie “provided Pacira with valuable insight and guidance” as it sought “to provide an opioid alternative to as many patients as appropriate.”

Mr. Christie has continued to consult for drug companies. In April, he joined the advisory board for Cytogel Pharma, a company testing a new non-opioid pain reliever in clinical trials.

Dean Maglaris, the chief executive of Cytogel, said Mr. Christie had helped connect the young company with industry experts and government officials.

“Being from New Jersey, which is the, probably the state with the largest population of pharmaceutical companies, he has put us in contact with people that he knows,” Mr. Maglaris said. Mr. Christie also helped connect the company with “folks in the federal government who have an abiding interest in solving the addiction crisis.”

Mr. Christie, a former federal prosecutor, also got involved in a high-profile money-laundering case. Mr. Christie was hired by Jho Low, a Malaysian businessman who had been indicted in 2018 on money laundering and bribery charges and was living as a fugitive. At the time, the U.S. government had seized hundreds of millions of dollars in assets tied to Mr. Low and associates.

Mr. Christie never registered in court as an attorney for Mr. Low, but he worked behind the scenes to negotiate a deal with Justice Department lawyers. Mr. Low ultimately forfeited nearly all of the seized assets — with the exception of $15 million in payments to Mr. Christie and two law firms.

The payout raised eyebrows among other lawyers involved. They saw it as a hefty sum for the legal work performed, but ultimately the Justice Department agreed to it, because the priority was to make sure Mr. Low did not have access to the money himself, according to people with knowledge of the negotiations.

Although Mr. Christie had been using his connections in the Trump administration as a consultant for years, he did not register as a federal lobbyist until June 2020, shortly after the pandemic hit.

As Congress passed several bills to help both businesses and health care providers, several major health care networks, all in New Jersey, hired Christie 55 Solutions: Atlantic Health System, RWJBarnabas Health and Hackensack Meridian Health each paid the firm $200,000 for a little less than a year’s work.

Christie 55 Solutions, whose small staff included Mr. Christie’s wife, Mary Pat Christie, and Rich Bagger, his former chief of staff, closed its federal lobbying shop in late 2021.

As he used his sway in Washington, Mr. Christie kept one foot in New Jersey. Both Mr. and Mrs. Christie joined a real estate venture with a New Jersey developer, Jon Hanson, a longtime political ally and fund-raiser for Mr. Christie’s campaigns.

Mr. Christie’s involvement was announced in 2019 as the enterprise, named the Hampshire Christie Qualified Opportunity Fund, set out to find investors for real estate developments taking advantage of federal “opportunity zones,” a Republican-backed tax program intended to benefit low-income neighborhoods. The Trump administration program has been criticized as a windfall for wealthy developers.

The Christies are “investor partners” in the fund and Mrs. Christie has helped raise some of the money, Mr. Hanson told The Times.

Karl Rickett, a spokesman for the Christie campaign, said the former governor was never involved in the fund as a senior adviser or in any other capacity, and that the venture was entirely a project of Mrs. Christie’s.

The fund has raised $80 million of its $250 million goal for three luxury housing and retail projects in Hackensack, N.J., and a New London, Conn., storage facility that will be developed by the firm Mr. Hanson founded, according to Mr. Hanson.

When the fund was first publicized, Mrs. Christie promoted her husband’s involvement as an advantage, saying he would use his connections to smooth the path with New Jersey mayors, town councils and zoning boards.

“Nobody really knows New Jersey as well as Chris, because he’s been at the helm for the last eight years,” she said to The Wall Street Journal at the time.

Mr. Hanson, however, has said that has not happened. Mr. Christie has not been involved at the local level, he said.

Kenneth P. Vogel contributed reporting. Kitty Bennett contributed research.