He earned a medical degree at Harvard Medical School and served as a captain in the medical corps of the U.S. Army for nine years. During a general surgical residency at UCSF, Maa was awarded a National Institutes of Health gastrointestinal research training grant, and published numerous scientific articles on pancreatic and gastrointestinal inflammation. He later completed a health care policy fellowship at the UCSF Institute of Health Policy Studies, where he researched ways to improve general surgical care nationally. This resulted in the implementation of the UCSF Surgical Hospitalist program at UCSF Medical Center in 2005 to improve the timeliness and quality of emergency surgical care, for which Maa was recognized nationally as one of "20 People Who Healthcare Better" by HealthLeaders Magazine in 2009.