Tim Scott, the Former G.O.P. Presidential Contender, Will Back Donald Trump

Senator Tim Scott of South Carolina will endorse Donald J. Trump on Friday evening at a rally in New Hampshire, according to two people briefed on the matter.

Mr. Scott was traveling to Florida on Friday so that he could fly with Mr. Trump to New Hampshire for the rally, the two people said. His endorsement of Mr. Trump is likely to spur additional discussion of Mr. Scott as a potential running mate for the former president. He is the highest-ranking elected Black Republican in the nation.

Mr. Scott arrived at his decision only recently. After ending his own campaign for president on Nov. 12, he had said he would not endorse “anytime soon.” But he came to the conclusion that Mr. Trump was the best candidate to defeat President Biden, according to one person familiar with his thinking.

A spokesman for Mr. Scott declined to comment. A spokesman for the former president did not immediately respond to a request for comment.

During the race, Mr. Trump avoided criticizing Mr. Scott, a sign that he held warmer feelings for the senator, whom he worked alongside while president.

Mr. Trump has pursued Mr. Scott’s endorsement since the senator exited the race last year. His endorsement not only lifts Mr. Trump in New Hampshire, which hosts its primary on Tuesday, but also in South Carolina, the home state of one of Mr. Trump’s top remaining Republican rivals, Nikki Haley. The Trump team is hoping to force from the race both Ms. Haley and Gov. Ron DeSantis of Florida with a decisive win in South Carolina’s primary on Feb. 24, avoiding an expensive fight for delegates that would otherwise extend through March after Super Tuesday.

The decision to back Mr. Trump could especially sting for Ms. Haley. As governor of South Carolina, she had appointed Mr. Scott to the Senate, announcing him as her choice more than a decade ago, in 2012.

Mr. Scott has fielded calls from all three of the remaining candidates in the race — Mr. Trump, Ms. Haley and Mr. DeSantis. Ms. Haley had called him this week and some mutual friends in South Carolina had also reached out to lobby on her behalf for his endorsement. Mr. Trump and South Carolina’s other senator, Lindsey Graham, a close ally of Mr. Trump, had lobbied him steadily. Mr. DeSantis also called Mr. Scott last year after Mr. Scott exited the race, according to the two people briefed on Mr. Scott’s endorsement decision.

The lobbying was a sign of how coveted Mr. Scott’s backing would be. While Mr. Scott struggled to gain traction in the primary, he remains overwhelmingly popular with Republican voters.

Surveys last fall from Public Opinion Strategies, a Republican firm that has worked with the DeSantis operation, showed Mr. Scott with a 78 percent favorability rating in South Carolina and a 67 percent favorability rating in New Hampshire.