Professor Khalid did his residency at the Alfred Hospital in Melbourne and underwent training for his FRACP in endocrinology at the Prince Henry’s Hospital where he also did his PhD with John Funder. He returned to join Universiti Kebangsaan Malaysia as a lecturer in 1982, and was later promoted to be Associate Professor in 1984 and Professor in 1990. He was the Dean and foundation Director of Hospital Universiti Kebangsaan Malaysia from 1990 to 1997 and 1996 to 2000 respectively. He was appointed as the foundation Professor of Medicine by Monash University Malaysia in 2004 and was the first Head of the Clinical School in Johor Bahru.
He was awarded the Tun Abdul Razak Research Award in 1986, the Asia Pacific Society Clinical Nutrition Award 1996, the National Science Award Malaysia in 1997 and also the joint winner of the MERDEKA Award for medicine, science and technology in 2008.
Professor Khalid was the president of several reputable societies, including the Malaysian Endocrine Society from 1995 to 1998, the ASEAN Federation of Endocrine Societies from 1992 to 1993 and Persatuan Diabetes Malaysia from 1985 to 1990. He was a Member of Council of the International Diabetes Federation, representing Western Pacific countries in 2000, and an elected member of the Malaysia Medical Council from 1986 till 2001. He was also the Master of the Academy of Medicine of Malaysia from 2005 to 2008 and Fellow of the Academy of Science Malaysia.
His main research interest is in Nutritional Stress in the pathogenesis of Metabolic Syndrome and investigating compounds for the treatment of diabetes and metabolic syndrome.