Ms Haley notably broke from Trump when she called for the US to continue to support Ukraine in its war with Russia.
When she later said she would vote for him in November, she said the former president would be “smart to reach out to the millions of people who voted for me”.
On Tuesday night, she told supporters of hers who might be on the fence: “You don’t have to agree with Trump 100% of the time to vote for him – take it from me.”
“Tonight is our unity night,” said New Hampshire state Senator William Gannon, who had served as a delegate for Ms Haley. He believed Trump made the right choice to invite her to speak.
“I wanna win the national election,” he said. “It was a wise move to bring her in.”
The third-place finisher in the primary, Florida Governor Ron DeSantis, received a far more enthusiastic welcome from the crowd.
He touched on several conservative social issues, including diversity initiatives, which he said were “indoctrination”.
He urged the crowd to rally behind Trump – though they were already solidly behind their current nominee. “We cannot let him down, and we cannot let America down,” Mr DeSantis said.
He also took a swipe at Mr Biden’s age, an issue that is currently roiling the Democratic Party. “We need a commander-in-chief who can lead 24 hours a day and seven days a week,” he said.
Daniel Willis, the 25-year-old chair of the Delaware Young Republicans, said Mr DeSantis and Ms Haley did more than enough “to bridge the gap” with Trump supporters.
The rest of the night was devoted to the more common Republican campaign points, such as migrant crossings at the border, crime and an overarching commitment to defeating Mr Biden.
Ted Cruz, the US senator from Texas, said there was a “literal invasion” of the United States. Dr Ben Carson, who served in Trump’s cabinet, accused Democrats of “shredding the Constitution”.
Trump himself led a huge standing ovation for Madeline Brame, a woman whose son was killed in New York in 2018 and has since called for tough-on-crime policies.
Down on the floor, delegates said they were ready to move beyond the intra-party divisions of the primary and instead focus the party’s energy on President Biden.
“At the end of the day,” said Georgia delegate Pam Lightsey, “We’re all Republicans.”
