[5] Having found his senior opportunities limited at Norwich City, Middleton joined Rangers on 31 January 2018,[6] reuniting with former Canaries youth coach Graeme Murty who was the Gers manager at the time of his arrival.

[3][4] Under Murty's successor Steven Gerrard, Middleton made his competitive debut for Rangers in a 2–0 win for Rangers against FK Shkupi in the Europa League on 12 July 2018 at Ibrox Stadium,[7] with Middleton being widely praised for his performance on his debut.

[9] On 26 October, Middleton signed a five-year contract with Rangers that tied him to the club until the summer of 2023.

[16] In July 2022, Middleton joined Dundee United from Rangers for an undisclosed transfer fee, on a three-year contract.

[18] Selected for the Scotland under-21 squad in the 2018 Toulon Tournament,[19] the team lost to Turkey in a penalty-out and finished fourth.