|Date of birth||May 21, 1971|
|Place of birth||Arima, Trinidad and Tobago|
|Height||6 ft 2 in (1.88 m)|
|1998–2000||Rochester Raging Rhinos||86||(1)|
|2001||Tampa Bay Mutiny||19||(0)|
|2002–2005||Rochester Raging Rhinos||78||(1)|
|2006||Virginia Beach Mariners||17||(0)|
|1995–2003||Trinidad and Tobago||7||(0)|
|Monroe Community College (assistant)|
|2011||Rochester Lancers (assistant)|
|* Senior club appearances and goals counted for the domestic league only|
Demmin attended Belhaven University, playing on the men's soccer team from 1990 to 1993. He was a 1991 Second Team and a 1992 and 1993 First Team NAIA All American. In 1992, Demmin and his team mates won the NAIA national men's soccer championship. In 2008, he was inducted into the school's Athletic Hall of Fame.
Demmin played for East Fife F.C. before playing in Major League Soccer for the Tampa Bay Mutiny in 2001. 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 represented the Trinidad and Tobago national team from 1995 to 2003.