The officeholder has the duty to enforce city laws, and the power to either approve or veto bills passed by the San Francisco Board of Supervisors, the legislative branch.

Prior to the conquest, Californios served as Mayor of San Francisco during the Spanish and Mexican eras since 1779.

Candidates must live and be registered to vote in San Francisco at the time of the election.

The new system, known as instant-runoff voting, allows voters to select and rank three candidates based on their preferences.

[10] Nine city public employees earned higher salaries than the mayor, including the chief investment officer and the managing director of the San Francisco Employees' Retirement System, who oversee the city's pension plan.

The mayor has the powers to either approve or veto bills passed by the San Francisco Board of Supervisors, participate in meetings of the Board of Supervisors and its committees, appoint a replacement to fill vacancies in all city elected offices until elections, appoint a member of the Board to serve as acting mayor in the absence of the mayor, and to direct personnel in the case of emergency.

There have been 45 mayoralties due to Charles James Brenham's serving two non-consecutive terms: he is counted chronologically as both the second and fourth mayor.

The longest term was that of James Rolph, who served over 18 years until his resignation to become the California governor.

During his term, San Francisco saw the expansion of its transit system, the construction of the Civic Center and the hosting of the World's Fair.

Thirteen mayors are native San Franciscans: Levi Richard Ellert, James D. Phelan, Eugene Schmitz, James Rolph, Elmer Robinson, John F. Shelley, Joseph Alioto, George Moscone, Dianne Feinstein, Frank Jordan, Gavin Newsom, Mark Farrell, and London Breed.