Konecny grew up dominating minor hockey in the Toronto area, including a minor-midget season (2012-13) when he scored 114 points (53 goals, 61 assists) in 54 games.
Ottawa then made him the No. 1 pick in the 2013 Ontario Hockey League Priority Selection Draft. Turning 17 during the 2013-14 season, Konecny led Ottawa with 70 points (26 goals, 44 assists), led all first year OHL players in goals and points and was named the league's top rookie. He finished the season by helping Canada place third at the 2014 IIHF World Under-18 Championship.