"Good evening, are you having fun?" Trump said as he addressed the crowd from the JumboTron.
WATCH LIVE: ABC News coverage of the Republican National Convention
Trump is the Republican nominee for president, no longer presumptive, and he and the party didn't wait for Thursday to make it official.
"What we did, getting the party's nomination. I'll never forget it," Trump said.
Trump's home state of New York put him over the top during the state by state roll call vote. California's vote was unanimous, 172 delegates in all, all in for Trump.
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Earlier, San Francisco delegate Harmeet Dhillon opened the proceedings with a Sikh prayer.
"I was very honored by the respectful response I got, and overwhelming response on social media from all over the world," Dhillon said.
Later, with the nomination secure, New Jersey Governor Chris Christie, a former federal prosecutor, made a case against Hillary Clinton for president.
"We cannot promote someone to commander in chief who has made the world a more violent and dangerous place with every bad judgement she's made," Christie said.
Then, Trump's grown children Tiffany and Donald Jr. took the stage an effort to show another side of their famous father.
"You want to know what kind of president he will be, let me tell you how he ran his businesses and I know because I was by his side on job sites, in conference rooms from the time I could walk," said Donald Trump Jr.
Two of Trump's once bitter rivals, Marco Rubio and Ted Cruz, will be the headliners Wednesday, along with Trump's running mate Mike Pence.
ABC7 anchor Reggie Aqui and reporter Laura Anthony are reporting live from the RNC in Ohio. You can follow them on social media: Click here to follow Reggie on Facebook and click here for Twitter. Track Laura Anthony on Facebook here and follow her Twitter here.
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