2009-10: Brown played for a powerful Toronto Marlboros Minor Midget AAA team that featured seven players who were taken in the 2012 NHL Draft. In 80 games he scored 25 goals with 44 assists and had 16 penalty minutes. Brown was selected by the Erie Otters in the 13th round (251st overall) of the 2010 OHL Priority Draft.
2010-11: Brown skated for the St. Michael's Buzzers in the Ontario Junior A Hockey League. In 49 regular season games he scored 17 goals with 22 assists and had 18 penalty minutes. The Buzzers finished fifth in the OJHL South Division and lost in the playoff qualifying round. In three playoff games Brown had 1 assist.
2011-12: Brown was the leading scorer for Erie in his first OHL season on a team that finished with the league's worst record. He played all 68 games for the Otters and had 25 goals with 28 assists and 14 penalty minutes; finishing minus-72 as Erie won ten games . Ranked 110th amongst North American skaters in Central Scouting's final rankings, he was selected by Toronto in the sixth round (156th overall) of the 2012 NHL Draft.