 Magnuson served as a private practicing attorney for 18 years in the firm of Levander, Gillen Miller and Magnuson, South Saint Paul, Minnesota, where his endeavors emphasized eminent domain and municipal law.Magnuson served as a lecturer at William Mitchell College of Law and Hamline University School of Law from 1982 to 1989.From 1986 to 1991, Magnuson also served as Jurist in Residence at a number of undergraduate college liberal arts campuses in Minnesota.