Dr. Flockhart is the Chief of the Division of Clinical Pharmacology at the Indiana University School of Medicine. He is the principal investigator of the Consortium on Breast Cancer Pharmacogenomics (COBRA) and of the NIGMS Pharmacogenetics Research Network site at Indiana University. He is actively involved in the mentoring of fellows in multiple medical disciplines and junior faculty through a K-24 award that supports his mentoring activities and through a Clinical Pharmacology training grant from NIGMS. He is actively involved in the Indiana University Cancer Center's Center for Pharmacogenomics, in PREGMED, the University's Center for the study of medications used during pregnancy, and in the General Clinical Research Center at Indiana University School of Medicine, which is supported by the division of Clinical Pharmacology pharmacogenetics Core Laboratory. His research is focused on clinically-relevant applications of pharmacogenetics and drug interactions.

He grew up in Edinburgh, Scotland and attended George Watson's College. He obtained a Ph.D. from the Welsh National School of Medicine and an M.D. from the University of Miami School of Medicine in 1987. He performed a residency in Internal medicine at Georgetown University Medical Center, and after a year as Chief Medical Resident, completed a fellowship in Clinical Pharmacology in the Division of Clinical Pharmacology at Georgetown University Medical Center.

He has been involved in the development of new pharmacogenetic tests using array, chip and other biotechnologies, and a focus of his research is to evaluate and communicate the value of pharmacogenetic tests to physicians and pharmacists involved in clinical practice. He has served on the Executive Committee and Board of the American Society for Clinical Pharmacology and Experimental Therapeutics and as Chair of the Government Affairs Committee. He serves on the editorial boards of Clinical Pharmacology and Therapeutics, the Pharmacogenomics Journal and Pharmacological Reviews and is an Executive Editor for the British Journal of Clinical Pharmacology.

His website, drug-interactions.com, a tool to improve rational prescribing, has been cited by the Washington Manual of Medicine and Therapeutics, The Harriet Lane Handbook for Pediatrics and the Medical Letter, and receives approximately 50,000 visits per year from physicians and scientists and around the world.