Dickinson was rated as a top prospect who fulfilled the expectation to be a first round selection at the 2013 NHL Entry Draft, being chosen 29th overall by the Dallas Stars. Dickinson joined the Guelph Storm of the Ontario Hockey League (OHL) for the 2011–12 season and was recognized for his stand-out play when he was named to the OHL Second All-Rookie Team. The following season he was invited to take part in the CHL Top Prospects Game, and was then selected to play with the gold medal-winning Canadian squad at the 2013 IIHF World U18 Championships. In the 2013–14 season, Dickinson helped the Storm capture the OHL championship before losing to the Edmonton Oil Kings in the Memorial Cup finals.