Callum made his first appearance for Scotland under-20 coming off the bench against England in the opening game of the 2016 Six Nations.
Previously, the lock received 10 caps at under-18 level, five of which he took charge of the team.
The lock has captained Edinburgh at under-17 and under-18 level, as well as appearing for Edinburgh Rugby A against their Glasgow Warriors counterparts and Ontario Blues.
He has since represented Glasgow Warriors in non-league fixtures.
In January 2017, he was called into the Scotland U20 squad for the Six Nations tournament, captaining Scotland in the championship.
He signed a two-year deal with Edinburgh in 2017 and made his Pro 14 debut for the side against the Cheetahs in November that same year.
In January 2018 he joined Newcastle Falcons on two-week loan and made an appearance for the side in the Anglo-Welsh Cup before re-joining Edinburgh.
On 13 September 2019 it was announced that he was joining Saracens on academy loan. He has since signed a long term permanent contract to remain at Saracens until 2023.[13]
He helped Saracens win the Premiership title in 2023, featuring as a replacement in the final as Saracens defeated Sale Sharks.
S.C June 2023
Career
 |
Saracens No 4 Lock |
2019 - present |
 |
Glasgow Warriors No 4 Lock |
2016 - 2017 |
 |
Scotland U20's No 5 Lock |
2016 - 2018 |
 |
London Scottish Tighthead Prop |
|
 |
Newcastle Falcons No 5 Lock |
2018 - 2018 |
 |
Edinburgh Rugby No 4 Lock |
2017 - 2019 |
 |
Scotland No 5 Lock |
2022 - 2023 |
