The couple said they were notified Wednesday that a staff member who worked closely in their living quarters had developed symptoms and tested positive for the virus, prompting the pair to get nasal swabs a day later.
The Democratic governor is not experiencing any symptoms of the virus but his wife has mild symptoms, his office said.
"Both remain in good spirits," Northam's office said in a press release.
“As I’ve been reminding Virginians throughout this crisis, COVID-19 is very real and very contagious,” Northam said in a statement.
“The safety and health of our staff and close contacts is of utmost importance to Pam and me. We are grateful for your thoughts and support, but the best thing you can do for us -- and most importantly, for your fellow Virginians -- is to take this seriously.”
Northam and his wife will self isolate for 10 days and continue to monitor their symptoms. His office said the two are working closely with the state Department of Health and the Richmond Health Department to trace their close contacts.
The Executive Mansion and Patrick Henry office buildings are closed Friday for deep cleaning.
Northam toured a socially distanced classroom at George Mason University on Tuesday and visited with several university officials and students as he announced a plan for higher education savings. He also visited a COVID-19 testing site at the university.
The Virginia Health Department has identified 144,433 positive cases of COVID-19 to date. Over 3,000 people have died of the virus in the state.
The news comes as President Trump is expected to hold a rally in Virginia on Friday night. Health officials warned a day before that the rally, which is expected to draw crowds of 4,000 people, would be breaking the governor's mandate banning gatherings over 250 people.
“The rally poses a concerning public health risk,” Dr. Natasha Dwamena, a Department of Public Health district director, said in the letter Thursday to the company that runs the venue where the rally will be held.