After captaining the Under-18s, Hamilton was moved into the Preserves squad. Further evidence of his progress came with a call-up to the Scotland Under-19 squad in October 2016. He has been called-up by Jose Mourinho, for the Emirates FA Cup tie at Huddersfield Town, where he replaced Paul Pogba as a substitute.
Hamilton enjoyed a superb season at underage level, netted the winner in the Premier League International Cup against Athletic Club.
This campaign, Hamilton become one of the first names on the team sheet for the Under-23 side. In addition, his impressive season he joined League One Side Rochdale on loan in January 2019 for the remainder of the season, however, he can move back to Manchester if he will show progression.