Kelly's legal career began with a clerkship to the Court of Appeal for Saskatchewan and continued with an associate's position at a major national law firm, where he obtained a broad range of litigation experience. He has represented clients before the Court of Queen's Bench, the Alberta Court of Appeal, the Federal Court of Canada, the Alberta Labour Relations Board, the Law Enforcement Review Board, and has appeared before numerous boards of arbitration and human rights panels.

He joined Field in 2007, where he primarily serves clients in disputes involving labour, employment, human rights and privacy issues. While he has developed a particular focus in management-side labour relations and employment law, he has also continued to hone his expertise in commercial litigation matters, and holds considerable expertise in the growing area of injunctive remedies. Kelly also has a special interest in police law, having served as general counsel to the Chief of Police for Calgary, and as counsel to the Calgary Police Commission and the Alberta Association of Chiefs of Police.