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 draft. Turning 17 during the 2013-14 season, he 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 win a bronze medal at the 2016 IIHF World Under-18 Championship.