The San Francisco Police Department identified the officer as 47-year-old Jack Nyce, but the department did not reveal the cause of death.
Nyce "served our city and our department honorably and well for more than 17 years," Police Chief Bill Scott said in a statement.
The San Francisco Police Officers' Association also issued a statement on Officer Nyce's passing, "Our heartfelt condolences go out to Jack’s wife, family, and friends. This is a sad time for our department. Jack leaves a void that will be difficult to fill. Rest in peace Officer Nyce."
Most recently the officer was assigned to San Francisco's Park Station.
Police officers and other first responders in San Francisco had been required to become vaccinated against the coronavirus by October 13.
Dozens of officers who were unvaccinated or in the process of getting a full dose of a COVID vaccine had been placed on leave in early November.