He received his medical degree from the University of Adelaide (Australia) and completed an internship at the Royal Adelaide Hospital (Australia). Dr. Sweeney did his residency in internal medicine at Gundersen Lutheran Medical Center (WI, USA) and a fellowship in hematology/oncology at Indiana University Medical Center (IN, USA), where he was later appointed Associate Director for Clinical Research for the Simon Cancer Center. Dr. Sweeney joined the Lank Center for Genitourinary Oncology at DFCI and Harvard Medical School (MA, USA) in 2009. 

His primary research interest is drug discovery and development. His academic focus is primarily on the management of genitourinary malignancies, with a focus on prostate and testicular cancer.