CLEVELAND — Vice President-elect JD Vance will resign his Senate seat at midnight Thursday, clearing the way for his swearing-in alongside President-elect Donald Trump on Jan. 20.

Vance, R-Ohio, notified Ohio Gov. Mike DeWine, who will choose his successor, of his plans in a letter Thursday afternoon. 

“To the people of Ohio, I extend my heartfelt gratitude for the privilege of representing you in the United States Senate,” Vance, who has served in the chamber for two years, said in a statement shared first with NBC News. “When I was elected to this office, I promised to never forget where I came from, and I’ve made sure to live by that promise every single day.”

Vance added that voters had issued “an undeniable mandate to put America first, both at home and abroad,” and pledged to work with Trump to “enact his agenda” over the next four years.

Vance, the author of “Hillbilly Elegy” and former venture capitalist, emerged as a political player in Ohio three years ago when Sen. Rob Portman, a Republican, announced his retirement. Vance entered a crowded GOP primary filled with better-known and better-funded candidates but rode a Trump endorsement to victory. 

Now, at 40, he will be the third-youngest vice president in history — behind John Breckinridge (36 years old upon taking office in 1857) and Richard Nixon (40 years and 11 days in 1953). 

DeWine, a Republican, will choose a replacement who will serve at least until a 2026 special election to determine who will fill the remaining two years of Vance’s term. 

DeWine’s lieutenant governor, Jon Husted, has emerged as the leading candidate but has not decided whether he wants the job.

Other Republicans on the short list include former Ohio GOP chair Jane Timken, state Rep. Jay Edwards and state Treasurer Robert Sprague. DeWine and Husted met with Trump last month at his Mar-a-Lago resort in Florida, but sources told NBC News that Trump made no commitments to Husted, who, amid the Senate speculation, has been preparing a campaign to succeed DeWine, who is term-limited, as governor.

“I’m not ready to make an announcement yet, but the announcement will be coming soon,” DeWine said at a news conference Wednesday with Husted at the Ohio Statehouse.

Husted told reporters at the news conference that he is “considering all of the options.”

Hayley Carducci, a Husted spokesperson, said Thursday that Husted had no additional comment.

DeWine addressed the Senate vacancy with reporters Thursday night while attending an event with Trump and other GOP governors at Mar-a-Lago.

“We certainly have been working on this for some time, and I’ll have an announcement probably next week,” DeWine said.

When asked what Husted might be thinking about the possibility of an appointment, DeWine declined to share details of their conversations.

“Well,” he said, “I’m not going to get into that tonight.”