Deputy Communications Director Alex Stack says Newsom is exhibiting "mild symptoms," while First Partner Jennifer Siebel Newsom tested negative.
The governor will work remotely and self-isolate, in accordance with California Department of Public Health's guidance.
Newsom is scheduled to make a "major" announcement with Attorney General Rob Bonta Thursday morning. No updates were provided on how that will proceed.
This is the second time in less than a year Newsom tested positive for COVID-19. He last tested positive in May of 2022 having "mild symptoms," and was prescribed the antiviral drug Paxlovid.
The governor is fully vaccinated and has received two booster shots.