A Dunedin resident and graduate of the University of Otago, Dean was admitted to the bar in 1984. He worked as a solicitor specialising in civil litigation until 1996, when he commenced practice as a barrister sole.

Dean is a member of the New Zealand Law Society and the New Zealand Bar Association. He practises in accordance with the English profession of barrister-at-law, which means he accepts instructions only via solicitors.

This does not mean Dean does not meet with and deal directly with clients. It means he works in conjunction with a client's solicitor and assists as required in dealing with the client's problem.