Dr. Donald M. Berwick, a longtime health care leader and former Democratic candidate for governor, will join the Health Policy Commission, a state agency that monitors health care costs.
Attorney General Maura Healey appointed Berwick to the commission Wednesday. Healey said Berwick also will serve as an advisor to her "as we work to create a more transparent and innovative health care system across this state."
The 11-member Health Policy Commission was created in 2012 as a watchdog agency to monitor health care industry mergers and track costs. The commission's membership is made up of health care experts, state officials, and business and labor leaders, five appointed by the governor and three each appointed by the attorney general and the state auditor.
Berwick is a senior fellow at the Institute for Healthcare Improvement, a Cambridge nonprofit that works with health care organizations around the world on patient safety issues. He founded the organization and ran it for nearly 20 years.
In 2010, President Obama tapped Berwick to run the federal Medicare and Medicaid programs, but Berwick left the post in 2011 after Republicans vowed not to confirm his permanent appointment.
Last year, as an unsuccessful candidate for Massachusetts governor, he pushed a liberal agenda that included a government-run-and-funded single-payer, or "Medicare for all," health system.
Berwick, a pediatrician, wrote an opinion piece for the Globe last year opposing a plan by Partners HealthCare, the state's largest health system, to acquire three community hospitals. In that piece, he called the Health Policy Commission a "nearly toothless but highly competent independent oversight body."
The commission also opposed the Partners deals, arguing they would raise medical spending and bolster Partners' market power.
Berwick said in an interview that he has spent much of his career toward one aim -- better health care at lower costs -- a goal shared by the Health Policy Commission.
"Massachusetts can and should be a leader moving toward the kind of effective and affordable health care system the country needs and wants," he said.
He will join the commission Jan. 1, replacing Dr. Paul Hattis, a Tufts University medical school professor who has served on the board since its founding in 2012.