Both members of the firm studied at the Massachusetts Institute of Technology. The firm was founded in 1887 or 1889, and continued until Underwood's death in 1921; Brown remained in business until his retirement in 1930.
The firm designed many landmark buildings in San Francisco and Oakland, including:
- First Church of Christ, Scientist (1898–1904)
- Palace Hotel (1898)
- Merchants Exchange Building (1901–1903)
- Union Trust Company Building (1907)
- Southern Pacific Building (1911)
- Shell Building (1929–1930)
Brown and Underwood were also involved in the design of several major infrastructure projects, including the Hetch Hetchy Reservoir and the San Francisco-Oakland Bay Bridge.
The firm's work is characterized by its use of Beaux-Arts and Art Deco styles, and its emphasis on grand, monumental forms. Brown and Underwood were also known for their innovative use of building materials, such as steel and concrete, and for their attention to detail.
Brown and Underwood's work has been widely recognized for its excellence, and the firm is considered one of the most important architectural practices in San Francisco history.