 In the 1920s and 1930s, Bergstrom was associated with the Pasadena architectural firm of Bennett and Haskell.He won a design competition in 1923 to design the City of Pasadena Civic Auditorium, which anchors the south end of the city's civic center.In the late 1920s, Bergstrom was one of five prominent Los Angeles architects, organized as the Allied Architects of Los Angeles, involved in designing the Los Angeles County/USC Medical Center General Hospital (1933), an architectural monument in East Los Angeles.