Joe Duffy was on the bench for Norwich City's Under-18 clash with Everton on 23rd November 2019. He then made his Under-18s debut in the 4-4 draw with Leicester on 4th January 2020. As a youngster, he was with Costessey Sports and attended Ormiston Victory Academy. He has been capped by England at Under-15 level.

9th August 2020 Norwich announced that six Academy youngsters, including Duffy, had signed with the Club as first-year scholars with the Canaries. He is described as an attacking midfielder.

He signed his first professional contract with Norwich in July 2021

On 5th May 2024 Duffy announced that he would be leaving Norwich at the end of the season. He made 83 appearances combined for the U18s and U21s in the last four seasons.  Writing on Instagram, Duffy said: "Just wanted to say a massive thank you to Norwich City for the last 12 years. Unfortunately, my time has come to an end at this amazing football club, but I am so grateful for the opportunity I've been given and memories made along the way with all the players and staff. I wish everyone the best for the future. I will always love and support this club, and it will forever hold a place in my heart."