Hoffman tweeted that the Marine, who he did not name, recently traveled overseas on official business and tested positive for COVID-19 on Saturday. He is currently being treated at Fort Belvoir Community Hospital.
The announcement so far marks the first positive case for an American servicemember stationed in the US.
Defense Secretary Mark Esper and the White House have been briefed on the development, Hoffman said.
On Friday a US Navy sailor stationed in Naples, Italy, became the first US servicemember stationed in Europe to test positive for coronavirus. And in a separate case last month, a US soldier stationed in South Korea tested positive -- the first US servicemember to do so.
The US Army, Air Force and Navy are now screening new recruits for the novel coronavirus as part of a sweeping effort to prevent the virus from spreading among the armed forces.