[1] Blumenthal was a professional staff member to the U.S. Senate Committee on Human Resources health and scientific research subcommittee in 1977 to 1979.

He became chief of the Health Policy Research and Development Unit at Massachusetts General Hospital in 1991 and director of the Institute for Health Policy for the Massachusetts General Hospital and Partners HealthCare System in 1988.

On March 20, 2009, President Obama appointed Blumenthal to be the National Health Information Technology Coordinator, just a month after the enactment of a federal stimulus package that included about $19 billion in incentives, by Medicare and Medicaid, for the adoption of electronic health records.

By many reports, he succeeded in putting in place one of the largest publicly funded infrastructure investments the US ever made in such a short time period, in any field.

Blumenthal's older brother, Richard, is a United States senator from Connecticut.