Mr. Dunham had two great wrestling coaches and role models - Bob Siddens at Waterloo West High School and Bill Koll at the University of Northern Iowa. The Distinguished Members of the National Wrestling Hall of Fame both helped shape his teaching and coaching philosophy.

Dan launched a 36-year career in education at Jesup High School with a four-year stint as the head wrestling coach. The 1968-69 school year he was the sophomore coach at Dubuque Senior High School before moving on to newly opened Dubuque Hempstead High School to become their first-ever coach.

He retired at the end of the 1999 season. Coach Dunham's teams compiled a 242-160 dual meet record with over 100 state qualifying athletes. He coached 48 medal winners, including seven state champions. Eight of his wrestlers went on to be NCAA All-Americans, and Cliff Moore, a three-time state champion, was an NCAA Division I champion and three-time All-American for the University of Iowa.

In 1996 Dan was honored by being named Class 3A State Coach-of-the-Year and in 1999 he was inducted into the Iowa High School Athletic Association Hall of Fame. From 1970-78 he also officiated high school and local college meets.

In his retirement ,he has worked with Dubuqueland Pheasants Forever Chapter and is listed as one of the Top 25 Pioneering National Volunteers for National Pheasants Forever. In 2010 the Iowa chapter inducted him into the Iowa Pheasants Forever Hall of Fame. Twice he has won the Iowa Governor's Volunteer Service Award and he is a certified Iowa Hunter Education instructor.