The 18-year-old - subject of an enquiry from Leeds in January - has agreed a three-year deal with United, who brought former Latics player Joe Gelhardt to the club last August for a £1m fee.
McGurk helped Wigan under-18s to the Professional Development League National championship last season as the north-west side secured back-to-back titles. The teenager hit 13 goals in the process.
The talented schemer also caught the eye in the club's 2019-20 FA Youth Cup run in scoring against Birmingham City and Manchester United.
The Liverpool-born player will link up with Mark Jackson's under-23 side, who will play in the Premier League 2 Division 1 next season.