After serving as city solicitor from 1901 to 1909, he became mayor of the city in 1911. As a city official, Baker's main interests were providing Cleveland with electricity (he built a municipal light plant), public transit reform, hospital improvement, and city beautification. He was a strong backer of Cleveland College, now a part of Case Western Reserve University. His crowning achievement as a mayor was the passage of the home rule amendment to Ohio's constitution, which was approved by voters in 1912. It granted Cleveland a right to draw its own charter and conduct the city business without state interference.