Newsom spent his youth in the San Francisco Bay area and graduated from Santa Clara University in 1989 with a Bachelor of Arts in Political Science. He is married to Kimberly Guilfoyle Newsom, a San Francisco Assistant District Attorney. His first taste of public office was in 1996 when he was appointed President of San Francisco's Parking and Traffic Commission. Later in 1996, he was appointed to fill a vacant seat on the Board of Supervisors. Voters re-elected him the Board of Supervisors in 1998, 2000 and 2002.
Aside from public service, Newsom has built several successful businesses in northern California. He is a partner/owner of the PlumpJack Wine Shop (his first business, opened in 1992), the PlumpJack Cafe, the Balboa Cafe, the Matrix/Fillmore, the Squaw Valley Inn, and the PlumpJack Management Group.
Newsom, a Democrat, ran for Mayor in 2003, winning a November primary with 42% of the vote and advancing to a December runoff against fellow Supervisor Matt Gonzalez, which Newsom won with 53% of the vote. During the runoff campaign, Newsom was endorsed by former Vice President Al Gore and former President Bill Clinton.