Courtenay has been a lawyer since 2000. He is a barrister (England and Wales) and an attorney (California). He is an adjunct professor of law at Pepperdine University. From the start of his career, he was involved in litigating numerous arbitrations. Since 2020, he has acted as an arbitrator in international seafarer disputes. As part of his practice as a lawyer, he has been involved in numerous commercial landlord and tenant cases.