2007-08: Chosen seventh overall by the Ottawa 67's at the 2008 OHL Priority Selection. Played for the Toronto Jr. Canadiens of the GTHL, where he was named MVP of the OHL Cup championship game.
2008-09: In his rookie season with the Ottawa 67's, Toffoli scored 17 goals and added 29 assists for 46 points in 54 games. He added 8 points in seven 2009 OHL playoff games, scoring 2 goals and adding 6 assists.
2009-10: In 65 games for the 67's, Toffoli scored 37 goals and added 42 assists for 79 points. He finished with a +25 rating and 54 penalty minutes. In 12 playoff games, he scored 7 goals and added 6 assists for 13 points. Toffoli played for Team Orr at the 2010 CHL Top Prospects Game.
2010-11: Toffoli made his pro hockey debut – appearing in one regular season game and five playoff contests for the AHL's Manchester Monarchs as an 18-year-old – following an outstanding season with the OHL's Ottawa 67's. Toffoli scored a goal in his only regular season contest with the Monarchs and in the five playoff games scored once and was -2 with 6 PMs. Toffoli skated in 68 games for the Ottawa 67's in his third OHL season and tied Kitchener's Jason Akeson (PHI) for the league lead with 108 points. Toffoli scored 57 goals with 51 assists and was a team-best +44 with 33 PMs as Ottawa finished first in the East Division. Toffoli scored 3 goals with 5 assists and was -4 with 4 PMs in Ottawa's wild four-game, first-round series with the Sudbury Wolves.
2011-12: Toffoli hit the 100-point mark for the second straight year and led the OHL in goals in his fourth season with the Ottawa 67's. Finishing two points behind Sudbury's Michael Sgarbossa for the OHL points lead, Toffoli scored 52 goals and had 48 assists in 65 games; finishing plus-31 with 22 penalty minutes. Ottawa was first in the East Division during the regular season and reached the playoff semifinals. Toffoli's 11 playoff goals were second only to Kitchener's Tobias Rieder (13) and he also had 7 assists in 18 playoff games; finishing minus-four with 21 penalty minutes. Three of his 11 playoff goals were scored on the Ottawa power play.
Toffoli has definite offensive skill, but it remains to be seen how much it will be on display at the pro level. If he reaches his potential, Toffoli should be one of the better offensive prospects from his draft class. His average skating ability could hold him back, though.