Democratic Lt. Gov. Gavin Newsom has won a chance for a second term.
The former San Francisco mayor grabbed 50 percent of the votes in Tuesday's primary.
Ron Nehring, former chairman of the San Diego County Republican Party and the California GOP, came in second with 23 percent of the vote. He had a large lead over two other Republicans, David Fennell and George Yang.
Nehring, who held the state party post from 2007 to 2011, is seeking to break the Democrats' monopoly in Sacramento, where they hold all eight statewide offices.
The top two vote-getters in Tuesday's primary advance to the November general election.