McManus has previously played for Celtic, Alloa Athletic Queen of the South, Greenock Morton, East Fife (loan) and Stranraer.
McManus played for the team in the 2013–14 UEFA Youth League and scored versus A.C. Milan on 26 November 2013 but the club was still eliminated from the competition.
[citation needed] In 2015, McManus won the Scottish Youth Cup, captaining the team to a 5–2 win over Old Firm rivals Rangers at Hampden Park.
On 24 March 2017, McManus signed an emergency loan deal at Queen of the South [5] and returned to Celtic at the end of the 2016-17 season.
In August 2021 he moved back permanently with East Fife but hugely missed most of 2021-2022 season with injury where the club was relegated to league two in the end.