The Sun newspaper says ( http://bit.ly/1gMlyLD) the 61-year-old certified public accountant was elected Tuesday in a vote that saw just a 14 percent turnout.
Davis defeated Wendy McCammack, who served on the City Council for 13 years until she was recalled in the same November election that saw her qualify for the mayoral race.
Davis, a corporate controller, got involved in politics last spring when he studied financial statements and concluded that the city had made years of bad spending decisions.
He will take over as mayor next month.
San Bernardino, located 60 miles east of Los Angeles, filed for bankruptcy protection after learning it faced a $46 million deficit.
Information from: The Sun, http://www.sbsun.com