Gerard Hanlon has been a member of the American Bar Association, New Jersey State Bar Association and the Morris County Bar Association. He is formerly a trustee of the county bar, and a former vice chair of the Morris County Bar's ethics committee. He is also a member of the New Jersey Association of Criminal Defense Lawyers. He is the long-time chairman of Harding Township's Juvenile Conference Committee. Hanlon has also served as master of Worrall F. Mountain Inns of Court, an ongoing development seminar for young attorneys. He is also active in his hometown of Harding Township once serving as president of the town's Historical Society and as a volunteer firefighter. He is also a member of the prestigious Baltusrol Golf Club.