Konecny was born on March 11, 1997, in London, Ontario. He grew up in nearby Clachan with his father Rob, a firefighter; mother Terri-Lee, a worker with autistic children; and brother Chase, an engineering student. Outside of his immediate family, Konecny's cousin Bo Horvat also played ice hockey from a young age. Because Clachan was too small to have its own ice rink, Konecny would practice on frozen ponds and would watch hockey games to develop his skills. He was also childhood friends with Lawson Crouse, who he met when they tried out for the same hockey team at the age of six. Coaches started to notice Konecny when, at the age of 10, he scored four goals and an assist in one period of a youth ice hockey tournament.
