Jim Miller was an NCAA Division II champion at 134 pounds for the University of Northern Iowa in 1974 and 1975 and placed second and fourth in Division I those same years.

After coaching at the high school level, Miller returned to UNI as the top assistant coach from 1983-91 when he became head coach at Wartburg. He had a career record of 413-37-2, winning 10 NCAA Division III team championships, 21 consecutive Iowa Conference championships and seven National Wrestling Coaches Association National Duals championships before stepping down after the 2013 season. He coached 37 individual national champions, 147 All-Americans and 72 NWCA Academic All-Americans at Wartburg.

Miller received the Lifetime Service to Wrestling award from the Iowa Chapter of the Hall of Fame in 2001. He is a member of the Division II Hall of Fame and the Division III Hall of Fame and Wartburg dedicated the Jim Miller Championship Mat in 2018. Miller was inducted into the University of Northern Iowa Hall of Fame in 2001 and into the Wartburg Athletic Hall of Fame in 2019.

He was named National Division III Coach of the Year in 1993, 1996, 1999, 2003 and 2009 and the National Assistant Coach of the Year in 1989. Miller was named Dan Gable Coach of the Year, which recognizes coaches from Division I, Division II and Division III, in 2004 and 2013. He was named Rookie Coach of the Year by Amateur Wrestling News in 1992 and received the Coaching Excellence Award from the National Wrestling Coaches Association in 1999.

Miller wrestled at East Waterloo High School and finished third in the state in 1971 and had a career record of 43-11.