Dr. Singh started his academic career as an Assistant Lecturer of Surgery at IOM, TU in 1991. He received Teachers Training on Helping Students Learn organized by the Institute of Medicine/WHO in 1992. After completing his postgraduate study in Japan, he was promoted to Lecturer of Surgical Oncology in 1999. He was awarded Fellow of the International College of Surgeons in General Surgery/Oncology in March 2001. He received a Short Course Training on Pain and Palliative Care from Calicut, Kerala, India in October 2003. Singh was promoted to Associate Professor and Professor of Surgical Oncology in 2004 and 2008, respectively.
Dr. Singh has been serving as Unit Chief of Surgical Oncology (Breast and Gastrointestinal) in the Department of Surgery, TUTH since 2009. He later received JICA training on Early Detection of Digestive Cancers from Keio University Hospital Tokyo in 2012. He has been serving as Head of the Department of Surgery, TUTH/MMC since February 2016. He has been credited with developing five surgical sub-specialty departments during his tenure.
He had served as the Research Director and Member Secretary of the Institution Review Committee in the Institute of Medicine from June 2016 to August 2021. Dr. Singh has also been contributing as a board member of the Nepal Health Research Council (NHRC) since 2017. He has been serving as Editor-in-Chief of the Journal of Institute of Medicine Nepal (JIOM Nepal) since April 2019.