He worked initially for Ernest George and Harold Peto in London from 1882–87, then opened his own office in Gravesend, Kent, in 1890. From 1902-1913 he developed his career in South Africa. In 1913 he returned to England and began practice in London in partnership with Alexander Scott. Near the end of this most productive phase of his career, Baker received a knighthood (in the 1926 King's Birthday Honours List), was elected to the Royal Academy, received the Royal Institute of British Architects' Royal Gold Medal in 1927, and received honorary degrees from Witwatersrand and Oxford Universities. Baker's autobiography "Architecture & Personalities" was published in 1944.