2010-11: Kelly Summers played or the Ottawa Valley Titans bantam AA team. He was selected by Carleton Place in the second round (20th overall) of the 2011 CJHL Draft.
2011-12: Summers skated in two games with the junior A Carleton Place Canadians as a 15-year-old — with no points or penalties — and spent most of the season with the Ottawa Valley Titans midget minor AAA team. He scored 9 goals with 22 assists and 20 penalty minutes in 30 regular season games and scored 3 goals with 6 assists and 6 penalty minutes in eight playoff games. Summers was selected by Oshawa in the sixth round (110th overall) in the 2012 OHL Priority Draft.
2012-13: Summers was named the CCHL's Rookie of the Year following his first season with the Carleton Place Canadians and in November committed to playing college hockey at Clarkson University in 2014-15. He scored 13 goals with 20 assists and 14 penalty minutes in 59 regular season games as the Canadians finished first in the Robinson Division. Carleton Place defeated rival Smiths Falls before falling to Cornwall in the playoff semifinals. Summers scored 1 goal with 1 assist and 4 penalty minutes in 12 playoff games.
2013-14: Summers had 43 assists, second only to Smiths Falls' Victor Beaulac (50) amongst CCHL defenseman and was named the CCHL's Top Prospect as Carleton Place captured the league championship. He also represented Canada East in the 2013 U19 World Junior A Challenge. Summers scored 17 goals with 12 penalty minutes in 56 games as the Canadians finished first in the Robinson Division. Carleton Place survived a seven game series with Pembroke in the semifinals before defeating Smiths Falls in the finals. Summers scored 5 goals with 8 assists and had 4 penalty minutes in 16 playoff games. The Canadians swept St. Jerome, Truro and Granby in the Fred Page Cup tournament to reach the 2014 Royal Bank Cup. Summers scored 2 goals with 2 assists and had 12 penalty minutes in four games for Canada East. He was ranked 73rd amongst North American skaters in Central Scouting's final rankings prior to the 2014 NHL Draft.