The vote makes it official that Trump, who has long been the presumptive nominee, will lead the GOP in a third consecutive election. The winner in 2016, he lost to President Joe Biden in 2020. In November, he will again face Biden.
Trump's announcement of Ohio Senator JD Vance as his choice for a vice presidential running mate has also been formally endorsed at the Milwaukee convention.
Donald Trump named JD Vance as his pick for running mate, shortly before his official nomination. (AP PHOTO)
The young Ohio senator rose to national attention with his best-selling memoir, Hillbilly Elegy, depicting a harsh life in rural America.
"As Vice President, JD will continue to fight for our Constitution, stand with our Troops, and will do everything he can to help me MAKE AMERICA GREAT AGAIN," Trump wrote on his Truth Social platform.
Vance, 39, and the author of best-selling memoir HillbillyElegy, was a fierce Trump critic in 2016 but has since become one of the president's staunchest defenders.
Trump's son Eric announced Florida's votes, which put the former president over the top for the nomination.
Delegates danced and waved Trump signs as the song Celebration played.
Throughout the voting, delegates flanked by 'Make America Great Again' signs applauded as state after state voted their support for Trump's second term.
Trump is due to formally accept the party's nomination in a prime-time address on Thursday
Saturday's shooting at a Pennsylvania rally, where Trump was injured and one man died, was not far from delegates' minds as they celebrated.
Some delegates chanted "fight, fight, fight" — the same words that Trump was seen shouting to the crowd as the Secret Service ushered him off the stage, his fist raised and face bloodied.
"We should all be thankful right now that we are able to cast our votes for President Donald J Trump after what took place on Saturday," said New Jersey state Senator Michael Testa.
After the assassination attempt, Trump said he was revising his acceptance speech to emphasise national unity rather than highlight his differences with Biden.
"This is a chance to bring the whole country, even the whole world, together. The speech will be a lot different, a lot different than it would've been two days ago," Trump told the Washington Examiner.
Republican Party chairman Michael Whatley said the convention's agenda will feature more than 100 speakers focused on kitchen table issues and Trump's plans to lift everyday working Americans.
Some well-timed good news was also affecting the mood on the convention floor. The federal judge presiding over Trump's classified documents case dismissed the prosecution because of concerns over the appointment of the prosecutor who brought the case, handing the former president a major court victory.
The US Justice Department will appeal against the ruling.
In addition to formally naming Trump the nominee, delegates from across the nation will turn to updating the GOP's policy platform for the first time since 2016.
The scaled-down platform proposal — just 16 pages with limited specifics on key issues, including abortion — reflects a desire by the Trump campaign to avoid giving Democrats more material on campaign issues.
The speaking program includes a handful of Republicans charged with crimes related to other political violence — the January 6, 2021, attack on the US Capitol.
Former White House adviser Peter Navarro, who's in jail for refusing to cooperate with a congressional investigation into the Capitol attack, is expected to speak at the convention just hours after his release.
Trump has repeatedly cast the people involved in efforts to overturn the 2020 election, including his many supporters who stormed the Capitol, as political prisoners.
Hundreds of demonstrators converged on downtown Milwaukee to protest around the convention, calling attention to issues such as abortion rights, economic justice and the war in Gaza.
The protesters' movements were restricted as part of enhanced security precautions established by the Secret Service.
Security officials previously announced that people just outside the Secret Service perimeter would be allowed to carry guns openly or concealed as permitted by state law.
Wisconsin statutes outlaw only machine guns, short-barrelled shotguns and silencers.
with AP
