Former Florida Gov. Jeb Bush listens before speaking at the National Summit on Education Reform in Washington in November. (Susan Walsh/AP)

Former Florida governor Jeb Bush, moving closer to a possible presidential run, has resigned all of his corporate and nonprofit board memberships, including with his own education foundation, his office said late Wednesday night.

He also resigned as a paid adviser to a for-profit education company that sells online courses to public university students in exchange for a share of their tuition payments.

Bush’s New Year’s Eve disclosure, coming in an e-mail from an aide to The Washington Post, culminated a string of moves he has made in recent days to shed business interests that have enriched him since leaving office in 2007. The aide said the resignations had been made “effective today.”

The aide said Bush was reviewing other businesses in which he is principal partner or owner, such as Jeb Bush & Associates, a consulting firm, and Britton Hill Partnership, a business advisory group that in 2013 set up private-equity funds investing in energy and aviation.

Aides said Bush wants to devote his time to exploring a return to politics rather than pursuing his business commitments. But separating himself from those interests now could also be a strategic attempt to prepare for the added scrutiny of a hotly contested campaign for the Republican nomination.

Bush’s financial stake in Academic Partnerships, the online education firm, has been relatively small for a millionaire — a $60,000-a-year fee and ownership of a small amount of stock, said Randy Best, the company’s founder and chief executive. Even so, Bush’s affiliation with the firm — which has contracts with schools in a half-dozen states and several foreign countries and has annual sales of $100 million — could complicate his effort to promote his record as an education reformer.

The company receives up to 70 percent of the tuition some students pay to public universities, and some faculty members say it siphons money from the schools while asserting too much control over academic decisions.

Best, a Texas entrepreneur and major political donor, said his firm has increased professors’ access to online students and helped schools attract additional revenue, while Bush aides say the former governor does not have business interests related to K-12 education, which has been his policy focus.

Bush’s decision to extricate himself from his private-sector work is “part and parcel of a process he is going through as he transitions to focus on a potential run for president,” said his spokeswoman, Kristy Campbell. “This is a natural next step that will allow him to focus his time on gauging interest for a potential run.”

The effort underscores the lengths to which Bush — who has become the favorite prospective candidate of many major GOP donors and has been at or near the top of polls testing the possible Republican presidential field — appears willing to go to avoid pitfalls that hurt the party in 2012. That year, GOP nominee Mitt Romney, founder of a private-equity fund, struggled to explain his business background while under attack by GOP rivals and President Obama.

Bush, 61, lamented Romney’s handling of the criticism in an interview last month with Miami’s WPLG-TV. Bush said the 2012 nominee allowed himself to be pulled “off message” and should have told voters: “I’m a problem-solver. My life has been about building things up.”

Of his own business record, Bush said: “I’m not ashamed. Taking risk and creating jobs is something we ought to have more of.”

Bush’s business portfolio is far smaller than that of Romney, whose Bain Capital became one of the country’s most successful private-equity firms. Yet it is complicated and could present political problems because he has been affiliated with a broad range of industries and businesses.

Bush announced last month that he was ending his consulting relationship with Barclays, the British investment-banking conglomerate. The New York Times reported in May that the company paid Bush more than $1 million a year.

The bank, like other major Wall Street players, had been under scrutiny in recent years for alleged interest rate manipulations and for allegedly providing special benefits to big traders.

Recent Securities and Exchange Commission filings revealed that Bush was leaving the boards of two publicly traded firms: Rayonier, which invests in forest lands, and Tenet Healthcare, which backed Obama’s health-insurance initiative and profited from its passage.

From Tenet, Bush has received nearly $2.1 million in director’s fees and restricted company stock since joining the board in 2007. The filings show that he sold some of his Tenet stock through the years. A March 14, SEC report showed that Bush held 59,403 shares of Tenet stock valued at the time at just over $3  million.

Academic Partnerships stood out in Bush’s business portfolio because it allowed him to combine a public policy issue he cared about with a business investment.

Bush’s reputation as an school reformer stems from his work on K-12 education as governor and as the head of his Foundation for Excellence in Education. He has been an advocate for online learning as a tool to expand opportunities for students.

While Bush’s association with the company began several years after he left office, Best contacted him about a possible business partnership before his departure from Tallahassee. The Texas businessman had connections to the Bush family, having raised money for the successful presidential campaigns of Bush’s older brother, George W. Bush.

After the two men met, Best sent Bush an e-mail in April 2005 touting a “huge global business opportunity” that could come from a “post-secondary initiative” he said they had previously discussed. He said he hoped Bush found the idea “intriguing.”

“If you are interested, let’s continue our discussions as you begin to think about returning to the private sector after you leave office,” Best wrote in the e-mail, which was obtained by The Post as part of a public-records request.

Bush responded that he had “pledged to myself to focus on my job until it is complete. I think I have a duty to do so.”

“Having said that,” Bush continued, “I think your vision is outstanding.”

Best said in an interview that he approached Bush at the time because he had heard that the governor might be looking for opportunities in the private sector. “I tried to get him in the water early,” Best said.

Years later, Best said, Bush was drawn to the firm because he has long been “intrigued by innovation in education,” particularly the goal of “bringing down the cost of higher education while maintaining quality.”

In his capacity as an adviser, Bush was “available to run ideas by and discuss concepts” as the firm expanded, Best said.

He said Bush helped preside over two conferences on the future of education hosted by the firm. Bush and former North Carolina governor Jim Hunt (D) helped draw a high-powered lineup of speakers, including Hillary Rodham Clinton, the likely Democratic presidential front-runner, who addressed a March meeting on global education.

A 2012 report by the Texas Tribune said the company received $105 million in revenue from 24 public colleges and universities, including eight in Texas. Forbes magazine reported in 2013 that the company had contracts with 40 U.S. schools.

Bush and Best wrote a 2013 article for Inside Higher Ed predicting that online classes would make higher education more accessible. “Companies like ours — Academic Partnerships — are helping universities respond to this transformative movement,” they wrote.

On some campuses, however, faculty members have viewed the arrival of Academic Partnerships with suspicion.

When the company arrived at Arkansas State University in 2011, for instance, faculty members were concerned “about a loss of quality and control,” said Jack Zibluk, a professor of media studies who headed the faculty senate at the time. Additional controversy erupted, he said, when some school officials involved in negotiations with the company later landed jobs with an affiliated firm.

Experts said that whether to do business with a contractor such as Academic Parternships remains a subject of great debate for university administrators.

“I don’t question whether firms like Academic Partnerships do quality work,” said Barbara Bichelmeyer, who directs online education for the seven campuses of Indiana University, which has chosen not to outsource its online learning programs. “The question we are engaging is about the ownership of the online educational experience — and whether a public institution is comfortable outsourcing this work in whole or in part.”

Best said that academicians’ concerns about his company — and online education generally — have largely diminished.

“It just increased their access to online students,” he said. The additional tuition received by schools “is revenue they would never have otherwise.”

Best said Bush called his cellphone Dec. 16, after announcing plans to explore a presidential bid, to let him know that he planned to resign from the company. Best said he plans to support Bush’s candidacy.

“He is the closest thing we have to a bipartisan candidate” who takes principled stands on tough issues such as immigration and education, Best said. “He is not going to be a person who responds to the polls or every change in the political winds.”

Alice Crites contributed to this report.