Johanson enrolled in the architecture program at the University of Washington in 1929 and graduated in 1934 with a B.Arch.
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 such as reinforcing architecture.
This joint venture worked so well that the partners continued it after 1945.
Johanson was one of the architects who joined together about 1950 to create the Hilltop community in Bellevue, Washington, a planned residential community of modern homes on large lots.
In 1950-51, Johanson served as the president of the Washington State AIA Chapter (predecessor to today's AIA Seattle Chapter).