On July 16, 1907, Taylor was appointed mayor following the resignation of Charles Boxton, who served only eight days after the conviction and removal of Eugene Schmitz.

Taylor was elected to a full two-year term that fall, defeating three other candidates (including future mayor P. H. McCarthy) with just over half the vote.

He declined to run again in 1909, and would be the last member of the Democratic Party to lead San Francisco for over half a century (until John F. Shelley was elected in 1963).

During his 30 months as mayor, Taylor's accomplishments included: presiding over the resolution of the bloody 1907 San Francisco streetcar strike; reorganizing the city government after 16 of 18 members of the board of supervisors and the chief of the police department were implicated in a corruption scandal; rebuilding the city in the aftermath of the devastating 1906 earthquake; battling with the federal government for the right to build the Hetch Hetchy water system; presiding over the creation of the Municipal Railway; and fighting an outbreak of bubonic plague.

[2] The political economist Henry George credits Taylor for influencing his work on Progress and Poverty, one of the most popular and influential books in American history.