Demmin attended Belhaven University, playing on the men's soccer team from 1990 to 1993.
[1] In 1992, Demmin and his team mates won the NAIA national men's soccer championship.
Demmin also had two stints with the Rochester Raging Rhinos, and was playing for the Virginia Beach Mariners at the time of their demise in 2006.
Demmin was named to the A-League All-Star Team five times while playing for Rochester.
Demmin is an assistant coach with the Monroe Community College women's soccer team.