Prior to calling to the Bar, Joe Cahill gained a valuable insight into police practice and procedure as a serving police officer and latterly detective. He was then involved in the prosecution of solemn cases over several years as a Procurator Fiscal Depute.

Since calling Joe has assisted senior counsel in a large number of murder cases as well as acting alone in the defence of cases of all kinds. He has defended a number of sex offenders and child abuse cases both in the High Court and at Sheriff and Jury level.