Newsom told the National Press Club in Washington, D.C. that the Healthy San Francisco program, begun in 2007, has since enrolled more than 30,000 city residents, halfway toward the city's goal of providing health care to an estimated 60,000 uninsured in San Francisco.
Officials had originally estimated the number of uninsured in the city at 82,000, but have since revised the figure down to 73,000, according to mayor's office spokesman Joe Arellano.
The 60,000-subscriber target represents the number of uninsured residents officials expect to sign up for Healthy San Francisco, Arellano said.
Calling the numbers "a historic milestone" for the tens of millions of Americans without health insurance, Newsom told the audience, "San Francisco is proving that it can be done," according to comments provided by the mayor's office.
"Healthy San Francisco is a program that can be duplicated across the country if our elected officials are willing to take risks instead of continuing the status quo," Newsom said.
The program, which is not health insurance, provides access to health care such as preventative, routine and emergency care, and substance abuse and mental health services, for uninsured adults ages 18 to 64. Quarterly fees range from no cost to $150, depending on monthly income.
Healthy San Francisco requires partial funding by San Francisco businesses with 20 or more workers -- an estimated $12 million out of the program's $200 million annual cost -- which has irked some employers.
The Golden Gate Restaurant Association has sued to halt Healthy San Francisco, alleging the employer spending requirement violates federal law.
The case reached a federal appeals court in April, where a decision is still pending, according to city attorneys.
In the meantime, the courts have allowed the program to proceed.