Johnson returned to the United States in 1982, where his first professional position was as music librarian at Old Dominion University (Norfolk, Virginia.) He entered the professoriate in 1985 at DePauw University (Greencastle, Indiana), where he spent his entire teaching career, beginning as assistant professor in 1985, tenured as associate professor in 1991, promoted to full Professor in 2000, University Professor in 2007, and Professor Emeritus in 2012. Despite his organist training, he did not teach organ but spent his career in the classroom and seminar room, teaching primarily Music History, Music Appreciation, and advanced topics courses in Musicology. He was an early advocate for first-year-experience education at DePauw, and taught many years in that program—both in January-term as well as semester-long courses, both in Music as well as non-Music topics.“An Approach to Integrating World Music, Improvisation, and Music History into a Single Course for First-Year Music Students” at the College Music Society, Great Lakes Chapter meeting, 2000 (Ball State University). He also brought Music into the Honors Scholar Program at DePauw, teaching a course on the “Art and Politics of Weimar and Nazi Germany,” examining the place of art, drama, literature, and music in the first four decades of twentieth-century Germany.
