2011-12: Sam Bennett played for the Toronto Marlboros Minor Midget AAA team in the Greater Toronto league and skated for the Marlboros in the 2012 OHL Cup. He scored 33 goals with 36 assists and had 34 penalty minutes in 37 regular season games. In seven games at the OHL Cup he scored 3 goals with 8 assists and had 10 penalty minutes as the Marlboros won a silver medal. Bennett was the ninth player taken when he was selected by Kingston in the first round of the 2012 OHL Priority Draft.
2012-13: Bennett skated in the OHL as a 16-year-old — being named to the league's all-rookie second team — and competed in the 2013 World Hockey Challenge and U18 World Junior Championship tournaments. He scored 18 goals with 22 assists in 60 regular season games for Kingston and was -2 with 87 penalty minutes. The Frontenacs finished third in the East Division despite a sub-.500 record and were swept by Barrie in a first round series. In four OHL playoff games Bennett had 3 assists and was -9 with 2 penalty minutes. He scored 3 goals with 4 assists and was +8 in seven games for gold medal-winning Canada at the WJC . In five games for Canada Ontario at the U17 WHC he scored 3 goals with 3 assists and had 10 penalty minutes.
2013-14: Bennett was an assistant captain for the gold medal Canada U18 team at the 2013 Ivan Hlinka Tournament before returning to Kingston for his second OHL season. In five games at the Ivan Hlinka tournament he scored 3 goals with 1 assist and was +3 with 6 penalty minutes.