Dr Mason is currently a Sessional Member of the Victorian Civil and Administrative Tribunal (Review and Regulation), and Senior Medical Advisor to Skilled Medical Pty Ltd. Dr Mason was previously the Secretary-General of the Australian Medical Association (AMA) (2004 - 2007) and CEO of AMA Victoria (1993 - 2004). Her other former roles include Chair of the Victorian Doctors' Health Program, a member of the Board of Health Purchasing Victoria (now HealthShare Victoria) and a Director of the North Western Melbourne Primary Health Network.

Dr Mason holds a Bachelor of Medicine and Surgery from the University of Melbourne, and a Master of Business Administration from Monash University. She is also a Fellow of the Royal Australasian College of Medical Administrators (FRACMA) and the Australian Institute of Company Directors (FAICD).