MILWAUKEE—It’s official: Former President Donald Trump is the Republican Party’s 2024 presidential nominee.

The announcement was made almost simultaneously with former President Trump’s announcement of his running mate, Sen. J.D. Vance (R-Ohio).

The GOP confirmed its nomination of the former president as the state of Florida added its delegates to the official count.

The roll call of states’ delegates began just before 2 p.m. CT.

Jeff Kaufmann, chairman of the Iowa GOP, made the nomination speech, saying that the former president was resoundingly chosen in primary elections that followed Iowa’s lead.

“This is a grassroots party!” he said, adding that that former President Trump is a champion of the people and “has kept his word!”

Mr. Kaufmann frequently punctuated his speech by pumping both fists in the air.

“It is my honor to nominate Donald J. Trump!”

Loud chants of “USA, USA, USA!” followed.

Nevada GOP Chair Michael S. McDonald seconded the nomination, saying that President Trump is fighting against “weaponized lawfare,” not only for himself but also for everyday people.

Corey Lewandowski said he was proud to cast New Hampshire’s 22 votes for “my good friend,” the former president. Mr. Lewandowski served as manager of candidate Trump’s successful 2016 presidential campaign.

The former president, who is 78 years old, faced criminal charges in four cases, one of which resulted in a conviction, and one of which was dismissed in the hours prior to the nomination vote.

Although the nomination of former President Trump was a foregone conclusion, the official action is a necessary and much-anticipated step toward the Nov. 5 general election.

The selection of former President Trump also takes on added emotional impact for the party faithful, considering his narrow escape—suffering only an injured ear—after a gunman opened fire two days ago at a rally in Butler, Pennsylvania.

The incident resulted in the death of a Trump supporter, while two other attendees were wounded. Police fatally shot the gunman; concerns about how he was able to scale a nearby building are being investigated.

In the wake of the violence, the former president and his presumed Democrat opponent, President Joe Biden, have both called for peace, unity, and calm as the run-up to the 2024 election continues.

Prior to the assassination attempt, the nation and world had been focused on President Biden’s performance in the June 27 debate with the former president. Following that face-off in Atlanta, the incumbent has fended off calls from a small group within of his party to drop out of the race. The 81-year-old president said that, despite age-related concerns, he is able and determined to fulfill his duties—and to serve a second term if he is re-elected.

The two men disagree on many key policies, including those surrounding the economy and immigration—both of which are high on voters’ lists of concerns, along with preserving Constitutional rights. Both sides have accused each other of being a “threat to democracy.”

In a major development on July 15, just before the convention began, a Florida federal judge threw out one of the criminal cases. The former president still faces sentencing in September after being convicted of criminal charges in New York.

But the former president’s lawyers are attempting to throw out the conviction in the wake of a U.S. Supreme Court ruling stating that presidents do enjoy immunity from having certain information used against them.

Biden Campaign Responds

While the incumbent supports abortion or “reproductive rights,” the Trump–Vance ticket is pro-life, President Biden’s campaign said.

The Biden campaign also disagrees with Trump–Vance concerns about the Affordable Care Act.

Further, the Biden campaign couched Mr. Vance as a person who enjoys support from “billionaires and corporations.”

“They know he and Trump will cut their taxes and send prices skyrocketing for everyone else,” the Biden campaign said.

Mr. Vance has questioned the validity of President Biden’s 2020 election win, the Biden campaign statement said, disagreeing with the refusal “to accept the results.”

The roll call of states’ delegates at the Milwaukee convention began just before 2 p.m. CT and concluded by 3 p.m.

House Speaker Mike Johnson (R-La.) announced that the former president had received 2,387 delegate votes, nearly double the total needed. He also announced that all of the former president’s children would escort him to accept the nomination, including his youngest son, Barron, 18, a recent high school graduate. The older children are daughter Ivanka Trump and sons Eric Trump and Donald Trump Jr. It is unclear when his acceptance speech will be made.