Dr Peh obtained his medical degree and Masters in Medicine (Psychiatry) from the National University of Singapore, is a fellow of the Academy of Medicine (Singapore) and is currently working in the area of general psychiatry.

He is currently a senior consultant with the Department of Psychological Medicine at Changi General Hospital (CGH) and is the programme director for the CGH Assessment and Shared Care Team (ASCAT), which is a community mental health project. Dr Peh is an clinical assistant professor with the Duke-NUS Graduate Medical School and senior clinical lecturer with NUS Yong Loo Lin School of Medicine. He is also part of the clinical faculty for the National Psychiatry Residency as well as for the Singhealth Family Medicine Residency.