After World War II, Harvard graduates were highly sought after, and like many of his colleagues, was offered a job right on the spot. He proceeded to follow his career path starting out as a draftsman for Marcel Breuer. He then became a researcher for the National Housing Agency in Washington, D.C., and later joined the architect firm Skidmore, Owings and Merrill in New York. In 1948, Johansen settled down and established his own practice in New Canaan, Connecticut to accompany four of his other colleagues, Marcel Breuer, Philip Johnson, Landis Gores, and Eliot Noyes. From 1955 to 1960, he was the adjunct professor at Yale School of Architecture, which had happened to become a vigorous center for modernism.