Johanson enrolled in the architecture program at the University of Washington in 1929 and graduated in 1934 with a B.Arch. While in school he was particularly influenced by Lionel Pries.
Johanson was initially employed by the Seattle firm Smith & Carroll, but within two years he was a partner in the firm, renamed Smith, Carroll & Johanson; the firm survived until 1951.
In 1943, during World War II, he joined with Floyd Naramore, William J. Bain, and Clifton Brady to form Naramore, Bain, Brady & Johanson (informally known as "The Combine" at the time) to undertake war-related projects. This joint venture worked so well that the partners continued it after 1945. Johanson remained a partner until his death. Today's NBBJ is the successor firm.
He married sculptor Jean Johanson in 1936. The couple had two children.
- Ochsner, Jeffrey Karl, ed., Shaping Seattle Architecture: A Historical Guide to the Architects, Seattle and London: University of Washington Press, 1994, page 346; ISBN 0-295-97365-X
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- Portrait, Progressive Architecture, 28 (November 1947), p. 12.
- Portrait, Progressive Architecture, 29 (December 1948), p. 50.
- Portrait, Progressive Architecture, 31 (September 1950), p. 57.
- Portrait, Architectural Forum, 89 (July 1948), p. 20.