David Simpson Knight began playing soccer with North Scarborough Soccer Club [NSSC) in Scarborough, Ontario. A club known for creating such talents as Julian de Guzman, formerly of Deportivo de La Coruña, and Jonathan De Guzman of Feyenoord, Andrew Ornoch of Telstar in the Dutch Eerste Divisie. The team was extremely successful and was granted an invitation to the famed Welsh International Super Cup, formerly known as the Ian Rush Tournament. In the summer of 1997 The North Scarborough Soccer Club (NSSC) took part in the Tournament and won their age group. Simpson was named Golden Boot Winner with a staggering 14 goals in 5 matches, landing him second only to Michael Owen for all time record holder.
The success of the Ian Rush tournament handed Simpson a tryout with Southampton of the Premier League. He would continue to play with North Scarborough until he was 17. He started his professional career at the age of 20, when he signed a lengthy deal with the Manchester United F.C. farm team, and Belgium first division side Royal Antwerp FC.
In 2005 he signed with the Toronto Lynx in the USL First Division. There he became a fan favorite often chatting with fans, and the media. After impressing with the Lynx he took another chance and left for Europe again and signed with Lombard-Pápa TFC in the Borsodi Liga in 2006, where he continued to impress. Lombard-Pápa TFC improved from six points at winter break, to 24 by the end of the season. Despite his efforts at the end of the 2006 season, Lombard-Pápa was relegated. Dave was sold and signed with Czech giants AC Sparta Prague in the summer of 2006 as one of the biggest Hungarian transfer deals that summer at 352.000 £.
Upon signing, David Simpson Knight became the first Canadian born player in history to be signed by the club.