Trump also promised to designate the white supremacist Ku Klux Klan and the anti-fascist group Antifa as terrorist organisations in his campaign rally in Atlanta.
President Donald Trump makes a series of promises at a campaign event in Atlanta in a bid to woo Black voters, including establishing Juneteenth, which commemorates the end of US slavery, as a federal holiday.
Trump, who announced the promises less than 40 days before the November presidential election, also pledged to designate two groups as terrorist organisations: the white supremacist Ku Klux Klan and the amorphous movement known as antifa that opposes fascism. He promised to increase access to capital in Black communities, create more jobs, support Black-owned businesses and expand opportunity zones.
Trump said he "will always put Americans first and that includes very, very importantly, Black Americans". He spoke at an event in Atlanta, a majority-Black city and the largest in Georgia, a state that could come into play in the November 3 election.
The speech and a fact sheet provided by Trump's campaign did not spell out how Trump would make good on his promises.
Only Congress has the power to create a federal holiday, but Trump could help introduce a measure for lawmakers to pass.
Calls to make Juneteenth, June 19, a federal holiday grew louder this summer as Black Lives Matter protests swept through the country and many organisations gave their workers the day off. The day is already recognized by 47 states and the District of Columbia. It marks when Union soldiers arrived in Galveston, Texas, and shared the news that slavery was abolished.
Hawaii, North Dakota and South Dakota do not have a holiday or other official observance of Juneteenth.
Trump is trailing Democratic opponent Joe Biden in national polling although the two candidates are neck and neck in several states that could be key to determining the winner of the election. Biden has campaigned with a message that Trump has mismanaged the coronavirus health crisis, which has devastated the US economy.
"Trump is making more empty promises," said Biden campaign spokesman Kamau Marshall.
More than 85 percent of Black voters belong to the Democratic party or lean toward it, according to the Pew Research Center.
Still, Trump told the Atlanta crowd that Biden "doesn't know Black Americans like I do."