"The only thing these corrupt politic will understand is an earthquake at the ballot box... and they're going to see it," Trump told some 20,000 supporters at the rally in the Amway Centre on Tuesday night.
"We did it once and we're going to do it again... and this time we're going to finish the job," Trump said.
"And that is why tonight I stand before you to officially launch my campaign for a second term as President of the United States."
Despite making the official announcement on Tuesday, Trump has been actively campaigning for re-election ever since he took office on January 20, 2017, holding dozens of rallies across the country over the past two-and-a-half years, reports Efe news.
"Our radical Democrat opponents are driven by hatred, prejudice and rage and want to destroy you and they want to destroy our country as we know it," Trump claimed, adding that this was "not acceptable. It's not going to happen".
The President also announced his official campaign slogan, "Keep America Great", following in the footsteps of his indelible 2016 slogan "Make America Great Again".
The Orlando event officially kicked off Trump's re-election campaign with more than 16 months to go until the November 2020 elections and over a year before the Democratic Party decides which of its current 24 presidential candidates will end up facing off against the incumbent leader.
The only Democratic candidate Trump mentioned by name was former Vice President Joe Biden, who is polling as one of the favourites to become the party's nominee.
Fundraising for Trump's re-election began nearly two years ago, when he had only been in the White House for five months.
Last October, Trump surpassed the $100-million mark in funds raised for his re-election, a figure that far exceeds the $11 million and $2.4 million that his predecessors Barack Obama and George W. Bush garnered, respectively, during their first two years in office.
( With inputs from IANS )