Dr Cheah obtained his medical degree from the University of Hong Kong. He returned to his home town of Ipoh, in Malaysia to practice his medical profession. While in Ipoh he had the opportunity to help with a group of fellow doctors to form the Perak Branch of the Malaysian GP College. He was also the president of the Perak Medical Society. Apart from his medical profession, Dr Cheah has also held the position of the president of the Ipoh Y.M.C.A. as well as the president of the Malaysian Y.M.C.A Council.
After migrating to Melbourne, Dr Cheah worked for a year in the casualty department of the Moorabbin Hospital, where he enjoyed instructing some of the medical students who were completing their placement rotations. Since then he resumed his profession as a solo General Practitioner in Bayswater until the end of September 2016 when he joined the team at Modern Medical Bayswater.