He obtained his MRCP after completing his postgraduate training in the UK and returned to Sri Lanka.
[7] He is a senior advisory board member to SACTRC (South Asian Clinical Toxicology Research Collaboration)[10] with Nimal Senanayake, Ravindra Fernando and Janaka de Silva.
He founded the OxCol (University of Oxford Colombo link) for studies on snake bites and yellow oleander poisoning.
[13] He has published academic articles on nephrology, organ transplantation, snake bites and oleander poisoning.
[14] Sheriff is also the founder and chairman of Western Infirmary Hospital in Colombo, a center for renal disease care, dialysis and transplantation.
[17] In 2019, Sheriff filed complaints with the Criminal Investigation Department over allegations which surfaced in social media which revealed that he treated Zahran Hashim, who was the prime suspect behind the 2019 Sri Lanka Easter bombings.