Callum lahir di Inggris. Segera setelah itu, keluarganya pindah ke pantai barat Skotlandia. Pada usia dini, Callum mulai bekerja dengan Teater Pemuda Skotlandia di Glasgow. Ketika dia berumur delapan tahun, Callum dan keluarganya pindah ke Amerika, tinggal di kota ski Vermont. Saat remaja, Callum menghabiskan satu musim panas belajar di Circle di Square Theatre School di New York City. Dia juga menghabiskan dua musim panas belajar di British American Drama Academy (BADA) di Oxford. Setelah lulus...
Callum lahir di Inggris. Segera setelah itu, keluarganya pindah ke pantai barat Skotlandia. Pada usia dini, Callum mulai bekerja dengan Teater Pemuda Skotlandia di Glasgow. Ketika dia berumur delapan tahun, Callum dan keluarganya pindah ke Amerika, tinggal di kota ski Vermont. Saat remaja, Callum menghabiskan satu musim panas belajar di Circle di Square Theatre School di New York City. Dia juga menghabiskan dua musim panas belajar di British American Drama Academy (BADA) di Oxford. Setelah lulus SMA, Callum kembali ke Inggris untuk mengikuti pelatihan klasik di Drama Centre di London. Sejak lulus, Callum telah bekerja di film, televisi, dan teater di AS dan Inggris.
Callum was born in England. Soon after, his family moved to the west coast of Scotland. At an early age, Callum began working with the Scottish Youth Theatre in Glasgow. When he was eight-years-old, Callum and his family moved to America, living in a Vermont ski town. As a teenager, Callum spent one summer studying at the Circle in the Square Theatre School in New York City. He also spent two summers studying at the British American Drama Academy (BADA) in Oxford. After graduating high school, Callum returned to the UK to pursue a classical training at the Drama Centre in London. Since graduating, Callum has worked in film, television, and theatre in both the US and the UK.