[1] Fagerson received his first call up to the senior Scotland squad by coach Vern Cotter on 19 January 2016 for the 2016 Six Nations Championship.

[4] He made his debut for Scotland as a replacement in the Six Nations match against England at Murrayfield on 6 February 2016.

[8][9] as of 24 November 2024[update] From the 2019-20 season Fagerson will be an assistant coach at Glasgow High Kelvinside.

[10] Outside rugby, Fagerson was Scottish Youth Downhill Mountain Bike Champion in 2010, sang with NYCoS National Boys Choir in 2006 and is a qualified lifeguard.

[11] Fagerson is known affectionately as "Zandbags" amongst Scottish rugby fans due to his love of getting involved in any "afters".