NORTH CHARLESTON, S.C. - South Carolina Sen. Tim Scott launched his presidential campaign Monday, offering an optimistic and compassionate message he’s hoping can serve as a contrast with the political combativeness that has dominated the early GOP primary field.

The Senate’s only Black Republican, Sen. Scott kicked off the campaign in his hometown of North Charleston, on the campus of Charleston Southern University, his alma mater and a private school affiliated with the Southern Baptist Convention. He repeatedly mentioned his Christian faith in his kickoff speech, crying, “Amen! Amen! Amen!” and at several points elicited responses from the crowd, who sometimes chanted his name.

But Sen. Scott also offered a stark political choice, saying “Our party and our nation are standing at a time for choosing: Victimhood or victory.” He added that Republicans will also have to decide between “grievance or greatness.”

“I choose freedom and hope and opportunity,” Sen. Scott said. He went on to tell the crowd that “we need a president who persuades not just our friends and our base” but seeks “commonsense” solutions and displays “compassion for people who don’t agree with us.”

That was a far cry from former President Donald Trump, who has played to the GOP’s most loyal supporters with repeated lies about his 2020 election loss as he campaigns for a second term in office. Florida Gov. Ron DeSantis, who could launch his own bid as soon as this week, has pushed Florida to the right by championing contentious new restrictions on abortion and LGBTQ rights and by seeking to limit the corporate power of Disney, one of his state’s most powerful business interests.

Sen. Scott, 57, planned to huddle with home state donors Tuesday, then begin a two-day campaign swing to Iowa and New Hampshire, which go first on the GOP presidential voting calendar.

His announcement event featured an opening prayer by Sen. John Thune of South Dakota, the No. 2 Senate Republican, who said, “I think our country is ready to be inspired again.” Republican Sen. Mike Rounds, South Dakota’s other senator, already has announced his support for Sen. Scott.

A number of high-profile GOP senators have backed Donald Trump’s third bid for the White House, including Sen. Scott’s South Carolina colleague, Lindsey Graham. Mr. Trump nonetheless struck a conciliatory tone Monday, welcoming Sen. Scott to the race and noting that the pair worked together on his administration’s signature tax cuts.

A source of strength for Sen. Scott will be his campaign bank account. He enters the 2024 race with more cash on hand than any other presidential candidate in U.S. history, with $22 million left in his campaign account at the end of his 2022 campaign that he can transfer to his presidential coffers.

Sen. Scott also won re-election in firmly Republican South Carolina—which has an early slot on the Republican presidential primary calendar— by more than 20 points less than six months ago. Advisers bet that can make Sen. Scott a serious contender for an early, momentum-generating win.

But Sen. Scott is not the only South Carolina option. The state’s former governor, Nikki Haley, who once served as Mr. Trump’s former United Nations ambassador, also is running.

Ben LeVan, a business professor at Charleston Southern who attended Monday’s event, said he hadn’t decided whom to support in the GOP primary but didn’t plan to back Mr. Trump.

“I really do hope that we can bring some civility back in politics,” Mr. LeVan said.

“That’s one of the nice things about Tim Scott, and quite frankly, Nikki Haley, and some of the other candidates as well. They’re more diplomatic, and that is something that I appreciate.”

Like others in the GOP race, including former Arkansas Gov. Asa Hutchinson and “Woke, Inc.” author Vivek Ramaswamy, Sen. Scott’s initial task will be finding a way to stand out in a field led by Mr. Trump and Gov. DeSantis.

One way Sen. Scott hopes to do that is his trademark political optimism. He said Monday that America’s promise means “you can go as high as our character, our grit, and our talent will take you.”

The Democratic National Committee responded to Sen. Scott’s announcement by dismissing the notion that Sen. Scott offers much of an alternative to Mr. Trump’s policies. DNC chair Jaime Harrison, who ran unsuccessfully for Senate in South Carolina in 2020, released a statement calling the senator “a fierce advocate of the MAGA agenda,” a reference to the former president’s “Make America Great Again” movement.

On many issues, Sen. Scott does indeed align with mainstream GOP positions. He wants to reduce government spending and restrict abortion, saying he would sign a federal law to prohibit abortions after 15 weeks of pregnancy if elected president.

But Sen. Scott has pushed the party on some policing overhaul measures since the killing of George Floyd, and he has occasionally criticized Mr. Trump’s response to racial tensions. Throughout their disagreements, though, Sen. Scott has maintained a generally cordial relationship with Mr. Trump, saying in his book that the former president “listened intently” to his viewpoints on race-related issues.

When he was appointed to the Senate by then-Gov. Haley in 2012, Sen. Scott became the first Black senator from the South since just after the Civil War. Winning a 2014 special election to serve out the remainder of his term made him the first Black candidate to win a statewide race in South Carolina since the Reconstruction era.

He has long said his current term, which runs through 2029, would be his last.