Kevin McCallum called in 2000 after 10 years as a solicitor both as a Procurator Fiscal Depute and in private practice. Having called to the Bar, he specialised in criminal defence work and Social Work Referrals. He joined Crown Office as an Advocate Depute in February 2004 and was thereafter appointed a Senior Advocate Depute in November 2006, before returning to defence practice in December 2009.

In recent years he has been responsible for the preparation and conduct of a significant number of intensive, large scale and high profile prosecutions often involving multiple accused.