Thier is a public health professional and institutional leader. Trained at MGH, he has served in the U.S. Public Health Service and led a number of prestigious institutions. In 1994 Thier became president of MGH and professor of Medicine and Health Care Policy at Harvard Medical School. From 1996 to 2002 he was CEO of Partners HealthCare. A Harvard professor position and an MGH building are named in his honor.