"Tonight @FLOTUS and I tested positive for COVID-19. We will begin our quarantine and recovery process immediately," Trump wrote on Twitter. "We will get through this TOGETHER!."
Trump previously tweeted that he and the first lady received COVID-19 tests Thursday night after top aide Hope Hicks tested positive for the virus.
"Hope Hicks, who has been working so hard without even taking a small break, has just tested positive for COVID-19. Terrible!" Trump wrote.
Hicks traveled with Trump frequently, including as recently as his trip to Cleveland on Tuesday for the first presidential debate.
White House spokesman Judd Deere issued a statement on Thursday night saying Trump "takes the health and safety of himself and everyone who works in support of him and the American people very seriously."
"White House Operations collaborates with the Physician to the President and the White House Military Office to ensure all plans and procedures incorporate current CDC guidance and best practices for limiting COVID-19 exposure to the greatest extent possible both on complex and when the president is traveling," Deere added.
In May, two White House staffers, including Trump's personal valet tested positive for the coronavirus, while Vice President Mike Pence stayed away from the White House for a weekend while three other members of the coronavirus task force quarantined after potential exposure to an aide who had tested positive.
Both Trump and Pence reported negative tests following those incidents.
National security adviser Robert O'Brien and Kimberly Guilfoyle, a Trump campaign official and Donald Trump Jr.'s girlfriend, also both tested positive for COVID-19 in July.