Dr. Seneviratne received his medical school training at the Faculty of Medicine within University of Colombo, Sri Lanka. He conducted his Residency and Fellowship programs at The University of Southern California in Internal Medicine, Medical Oncology and Hematology. In addition, Dr. Seneviratne was a Research Fellow in Molecular Biology and Genetic Engineering at the University of San Francisco Medical Center. Dr. Seneviratne has supported the Los Angeles Medical Community by teaching at The University of Southern California. In 2003, Dr. Seneviratne entered private practice and joined the Los Angeles Cancer Network. Dr. Seneviratne was voted by his peers one of LA Magazine's Top Doctor in 2020, 2021, and 2022. 

Dr. Seneviratne is widely published in numerous peer journals in the field of Hematology and Oncology, including The American Society of Clinical Oncology, Journal of Acquired Immune Deficiency Syndrome and Journal of the American Society of Hematology.