Callum holds a Doctorate of Musical Arts from Michigan State University, where he studied with Suren Bagratuni. While at MSU Callum was a teaching assistant to Professor Bagratuni and principal cellist of the MSU Symphony Orchestra. Prior to his studies in the USA he completed his Masters degree in cello performance at the University of Waikato, studying with James Tennant. Callum has taken part in masterclasses with Gautier Capucon, Alexander Ivashkin, Laurence Lesser, Leslie Parnas, and Thorlief Thedeen.

In 2014 Callum toured for Chamber Music New Zealand as a member of the Rangitoto Piano Trio, which was recorded live in concert for broadcast on Radio New Zealand, and he recently recorded the six Michl bassoon quartets for Atoll Records with his two sisters and bassoonist Ben Hoadley.