New Hampshire Gov. Chris Sununu, a frequent Republican critic of former President Donald Trump, said Monday in an exclusive interview with CNN's Dana Bash that he will not seek the party's 2024 presidential nomination.

Sununu's decision further defines the GOP's 2024 field and means there won't be a home-state contender in New Hampshire, leaving the Republican contest in the first-in-the-nation primary state wide open.

The governor, a popular figure in the Granite State, was reelected to a fourth two-year term in the fall. After his victory, he declined to rule out a presidential campaign for months, telling Bash last fall that the Republican Party is "clearly moving on" from Trump.

Sununu has also said the Republican Party's messaging needs to be more inspirational and less combative, a tonal shift from several prominent GOP politicians.

"I think the Republican Party as a whole just wants to get out and fight as opposed to saying, 'Look, let's remember what we're about -- limited government, local control, believing in individual responsibility. That's the live-free-or-die spirit of New Hampshire, and the model works really well," the governor told Bash then.

Sununu, who voted for Trump in both 2016 and 2020, has previously told CNN that whoever becomes the GOP nominee will have his support.

"Yes. I'm a Republican. I'm going to support the Republican nominee, because I can guarantee they're better than any of the Democrats that will likely sit in that presidential seat," Sununu said in a February interview with CNN's Alisyn Camerota. "I don't think it's going to be Donald Trump, but yeah, I'm going to support the Republican nominee, to be sure."