2009-10: Brock McGinn skated for the Guelph Junior Storm minor midget AAA team. In 52 games he scored 22 goals with 34 assists and had 69 penalty minutes. He was selected by the Guelph Storm in the third round (46th overall) of the 2010 OHL Priority Draft.
2010-11: McGinn played 68 games for the Guelph Storm in his first OHL season. He scored 10 goals with 4 assists and was plus-three with 38 penalty minutes as a rookie. Guelph, after finishing fourth in the Midwest Division, lost to Saginaw in the first round. McGinn was scoreless and minus-two with 2 penalty minutes in six playoff games.
2011-12: McGinn was named an assistant captain for Guelph in his second season but appeared in just 33 games – missing over two months after suffering a wrist injury in December. He scored 12 goals with 6 assists and was minus-two with 25 penalty minutes. McGinn skated in all six playoff games during the Storm's series with Plymouth. He scored 1 goal with 1 assist and was minus-three with 8 penalty minutes. McGinn was invited to the NHL Draft Combine and ranked 49th amongst North American skaters in Central Scouting's final rankings prior to the 2012 NHL Draft.
There is no question that McGinn has the competitive demeanor to play at the NHL level. McGinn is not a skilled forward, but instead a hard-working player who is willing to get his nose dirty while making sure that he is shutting down the offensive players from the opposing team. His future is primarily as a third- or fourth-line checking forward who will be a thorn in the side of opponents.