Johnson and Larry Yoder took over the Mustang softball program in the fall of 2006 and were co-head coaches from 2010-12. They were named the 2010 Midwest Collegiate Conference Coach of the Year after leading Mount Mercy to the MCC regular season and tournament championships. The Mustangs also earned their first NAIA national tournament berth since 1990. The 37 wins were the second most in school history, just shy of the 39 victories by the Mustangs in 1996.
Under Johnson and Yoder, the Mustangs have rewritten the offensive record book. They've set single-season school records for slugging percentage, total bases, doubles, home runs, and stolen bases. Defensively, the 2010 squad held opponents to the lowest batting average in school history and broke the strikeout and shut out records.
Johnson has been president of the Cedar Rapids Girls' Fastpitch Softball Association since 1990 and has also coached a girls' ASA traveling softball team, the Cedar Rapids Blue Devils, for 17 years. He has been a member of the National Fastpitch Coaches Association (NFCA) for 16 years, holding a Three-Star Master Coach Certification from the NFCA. Johnson, a patent lawyer with Nyemaster, Goode, West, Hansell & O'Brien, graduated from Northern Colorado in 1973 and earned a J.D. from Iowa in 1975.