Chuck Hagel, the former Republican senator tapped to become the next secretary of defense, has gone on a charm offensive in the lead-up to his confirmation hearing on Thursday, attempting to beat back a well-funded, aggressive campaign that has sought to depict him as an anti-Israel, homophobic politician eager to gut the Pentagon’s budget.

Hagel’s pushback during meetings with more than 50 senators and leaders of special interest groups this month appears to have been effective, said an official helping him prepare for the hearing.

The effort to vilify Hagel and his record, which began when his name was first floated for the job in December, has remained at a buzz but has not reached the type of crescendo that has doomed high-profile political nominations in the past.

“We’ve had a very aggressive strategy for tackling some of the issues that have been raised,” the Hagel aide said Wednesday, speaking on the condition of anonymity to discuss the nominee’s outlook. “I think we’re in a good place.”

That’s not to say Hagel’s confirmation is a forgone conclusion, supporters concede. Critics have piled onto the initial critiques with charges that Hagel’s ties to defense contractors and other private-sector firms may create conflicts of interest. They also have criticized his support for a global movement to eliminate nuclear weapons.

Sen. Carl Levin (D-Mich.), the chairman of the Senate Armed Services Committee, said Hagel will face tough questions about his past statements. Democrats outnumber Republicans on the panel 14 to 12, but committee insiders say they are not assuming that Hagel will get the vote of every Democrat.

“The confirmation will not be an easy one,” Levin said in a recent interview. “On the other hand, a lot of people who have worked with Hagel remember him as someone who was effective here, involved in foreign affairs, well-qualified.”

Hagel, 66, a Vietnam veteran, is counting on those bonds, the aide said.

“If you read the tea leaves, I think he might get more Republican votes than people might think,” the official said. “Those relationships are important.”

After Thursday’s hearing, senators can submit additional written questions to Hagel. The committee and the full Senate could vote next week.

Hagel’s opening remarks will offer a blunt rebuttal to his critics, including conservative groups formed to foil his nomination. The official helping Hagel prepare said he also intends to offer a clear-eyed view of the Pentagon’s fiscal challenges, convey his commitment to preventing Iran from developing nuclear weapons and voice strong support for the U.S. alliance with Israel.

Opposition from gay rights advocates over disparaging remarks Hagel made in 1998 about an openly gay man nominated for an ambassadorship has largely subsided. James Hormel, the former diplomat Hagel disparaged as “aggressively gay,” endorsed him this week, saying he believes that Hagel’s views have evolved. Hagel has said he is committed to expanding benefits to same-sex military couples.

The former senator will also say that he will try to avoid the across-the-board spending cuts known as sequestration, which will come into effect March 1 if the White House and lawmakers do not reach a deal — a prospect that appears increasingly likely.

Sen. James M. Inhofe (Okla.), the ranking Republican on the Armed Services Committee, said he and other senators who oppose Hagel have not been convinced by his efforts to clarify, retract or expand on previous positions.

He said Hagel’s perceived lukewarm commitment to Israel’s security will probably be the nominee’s chief vulnerability.

Inhofe and five other Republican lawmakers opened a new line of inquiry this week, asking Hagel in a letter to answer detailed questions about his ties to several companies that together paid him more than $1 million last year.

M.I.C. Industries, a Reston firm, paid Hagel $120,000 last year. Since 2008, the company has received more than $50 million in Defense Department contracts, according to federal contracting records.

Hagel received $116,000 last year from Chevron, which has billed the Defense Department more than $1.5 billion since 2008.

It is not uncommon for high-profile former lawmakers to land lucrative consulting fees and posts on company boards. Following protocol, Hagel has agreed to divest his stocks in Chevron and the McCarthy Group, a financial firm he ran after leaving the Senate in 2008, and sever ties with other organizations, including Georgetown University, where he has taught since 2009.

Hagel became a star professor at the university’s Walsh School of Foreign Service, where his geopolitics class routinely had a waiting list. Michael Podberezin, 27, who took the class last fall, said students admired Hagel’s informed, nuanced views on current events.

Podberezin, an Israeli citizen who served in his country’s armed forces, said he debated with Hagel on policy issues, including whether Israel should attack Iran’s nuclear program and the United States’ response to Syria’s civil war.

The student said that he was more hawkish than Hagel on both but that the former senator was never dismissive of his views.

“He is very open to hearing other people’s opinions,” Podberezin said. “But he’s very upfront about what he believes, and he doesn’t sugarcoat it.”

Julie Tate contributed to this report.