A Celtic Youth Academy graduate, Calum joined Killie in the summer of 2017 after impressing in League One for Alloa Athletic.
He made his Premiership debut at Pittodrie in a 1-1 draw with Aberdeen, making seven appearances in total in his first season.
His second involved a loan spell with Sligo Rovers in the League of Ireland before gaining valuable top flight experience with St Mirren during 2019/20.
Calum started the 2020/21 campaign before undergoing surgery on a hernia injury.
He signed a new contract with the club until the summer of 2022.