Collyer, 20, came off the bench in the second half of United's narrow Community Shield defeat against Manchester City on Saturday, taking our tally of Academy graduates to 251.
Late last season, Ethan Wheatley became the 250th Academy graduate play for the men's first team when he featured against Sheffield United back in April.
Collyer impressed Erik ten Hag during pre-season, featuring regularly during Tour 2024, presented by Snapdragon, and was rewarded for his efforts with an appearance at Wembley against our local rivals.
The 20-year-old replaced Kobbie Mainoo in the 59th minute under the arch and received warm applause from the Reds fans as he took to the field.