Alderson began his career with Toronto-based club
Portugal FC in the
Canadian Soccer League Reserve Division. In 2011, he joined
Vancouver Whitecaps FC U-23. He impressed the under-23 side and appeared in two matches with Whitecaps FC in the
2011 MLS Reserve Division. On November 17, 2011 it was announced that Alderson would be joining the club's senior side for the 2012 season. He made his debut in a 2–1 win against the University of Victoria Vikes, coming on as a substitute in the Whitecaps third pre-season match of the season. Alderson was released from his contract with Vancouver on November 14, 2014. In May 2015, Alderson joined
Fortuna Düsseldorf II of the
Regionalliga West. Alderson announced his retirement from professional soccer in 2017 following several ankle injuries. ==International career==