MARCO ISLAND, Fla. — With his convincing White House victory this month, President-elect Donald Trump's grip over the Republican Party is firmer than ever.

But a popular Republican governor who has long been a vocal critic of the former and future president says that there's still room in the GOP for those outside of the MAGA and America First base.

"The party is a big-tent party. There's no question about it," Sununu said in a Fox News Digital interview this week along the sidelines of the Republican Governors Association winter meeting, which was held at a waterfront resort in southwest Florida.

Sununu, who was a top surrogate and supporter of former U.N. ambassador and former South Carolina Gov. Nikki Haley, Trump's final challenger in the 2024 GOP presidential primaries, backed the Republican nominee in the general election.

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"It was a huge victory across the country, and the people of this country have spoken very loudly and unequivocally," Sununu said of Trump's electoral college and popular vote victory.

And the governor acknowledged that Trump is "the standard-bearer of the party" and "the voice of the party."

"But this is a very large party. If it wasn't, he (Trump) wouldn't have won. If it wasn't, we wouldn't have had convincing wins all across this country in a variety of different states," Sununu said.

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Asked about the president-elect's flurry of announcements on Cabinet nominations this month, Sununu said that "he definitely has a couple of controversial Cabinet picks that … I don't mind saying I'm not the biggest fan of, but the vast majority of them are terrific." (Sununu was interviewed before former Rep. Matt Gaetz, R-Fla., withdrew his name from consideration as attorney general amid a growing scandal.)

"He's bringing folks from the private sector, he's bringing in governors, he's bringing in folks that have real experience in all of these issues and that understand the mission, which is fiscal responsibility," Sununu said, "getting regulations out of the way, which effectively lowers costs on business, lowers costs on consumers, lowers costs for everyday citizens."

Sununu didn't stump on Trump's behalf in swing state New Hampshire, but he crisscrossed the campaign trail on behalf of down-ballot Republicans. The governor was a top surrogate for former Sen. Kelly Ayotte, the GOP gubernatorial nominee who emerged victorious on Election Day and has pledged to continue the Sununu agenda.

Asked if Ayotte's nearly nine and half point win was also a victory for him, Sununu said, "It was a victory for New Hampshire."

"Kelly's going to be phenomenal. She has that experience as an attorney general, as U.S. senator. She understands how the systems work," Sununu said. "Our transition is already going incredibly smoothly; discussions virtually every single day about all aspects of government, where it's going, how to build good teams and, most importantly … the opportunities to listen to what's happening in the communities."

"She'll have my cell number. I don't know if she'll need it, because I think she's going to be fantastic on her own, but she'll always have my cell number," Sununu said when asked if he'd be offering advice to his successor.

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And pointing to his two Democrat predecessors as governor, who Sununu said shared their cellphone numbers with him: "We want New Hampshire to be successful. So it's not just me helping Kelly out. It is always a team effort. She's going to have a host of people that she can lean on for any advice when she needs it."

After mulling a 2024 White House run, Sununu announced in the summer of 2023 that he would launch a presidential campaign, and weeks later he also said he wouldn't seek an unprecedented fifth two-year term steering the Granite State. (New Hampshire and neighboring Vermont are the only two states in the nation to hold gubernatorial elections every two years.)

"I'm excited to get back to the private sector. I like businesses, I like deal sourcing," he said. "I'm not sure exactly what the private sector is going to bring, but I think it's going to be pretty exciting."

New Hampshire will likely have a competitive Senate contest in 2026 when longtime Democrat Sen. Jeanne Shaheen, a former governor, is up for re-election.

But Sununu reiterated what he told Fox News Digital in July.

"Definitely ruling out running for the Senate in 2026. Yeah, definitely not on my dance card," he said.

But the governor predicted that Republicans will "have a good candidate. There's no question about it. A couple of different folks that might be interested in running. I think that'd be fantastic. We've had an all-Democrat [congressional] delegation for a long time. I think the people in the state, especially with Kelly's convincing win, would love a different voice, would love just some sort of change."

Asked if there's another run for office in his future, the 50-year-old governor said he's "not thinking about that at all, excited for the private sector. And that's all … that's in my windshield."

But he didn't entirely shut the door, adding, "We'll see what political chapters write themselves down the road."