Prior to turning professional, Dello played four seasons at the University of Notre Dame from 2016-20, tallying 40 points (7-33-40), a plus-19 rating and 133 penalty minutes in 154 games. He helped the Fighting Irish win a Big Ten Conference championship in 2017-18, in addition to consecutive Big Ten Tournament titles in 2018 and 2019. Dello also registered 36 points (7-29-36), a plus-22 rating and 186 penalty minutes in 152 games with the Tri-City Storm in the United States Hockey League from 2012-16, captaining the Storm to a Clark Cup championship in 2016. He was named the recipient of the 2015-16 Curt Hammer Award, presented annually to «the USHL player who distinguishes himself both on and off the ice by demonstrating outstanding performance skills, pride and determination.» The Lakewood, Ill., native won a bronze medal with Team USA at the 2014 Ivan Hlinka Memorial Tournament, finishing with two assists and six penalty minutes in five games.