As an EIS Fellow he worked under Dr. James Watt (soon to be named Director of the new National Heart Institute) (NIH), studying how fly eradication dampened outbreaks of childhood diarrheal diseases and about DDT's efficacy in combating typhus.

Only weeks earlier, then-Surgeon General Luther Leonidas Terry had appointed him to succeed James Watt as Director of NIH.

Stewart found himself at the helm of PHS under pressure both to expand his agency because of Medicare and Medicaid and to cut back because of the war in Vietnam and a slowing of the phenomenal growth of NIH.

His response was to weave PHS into the Johnson Administration’s creative approaches to federalism, using the highly successful Hill-Burton hospital construction program as a starting point for efforts to improve access to services through government planning.

Soon after Stewart became Surgeon General, for example, PHS took on the high-profile and critical task of certifying the nation’s hospitals for compliance with Title 6 of the Civil Rights Act of 1964, prior to the July 1966 implementation of Medicare reimbursement for health services.

As a result of the two reorganizations, his successor would report as a senior advisor to the Assistant Secretary for Health and Scientific Affairs, a political appointee, and would not even be appointed until well into President Nixon’s first term.

When the second reorganization took place the following spring (1968) the Assistant Secretary for Health and Scientific Affairs for DHEW, Dr. Philip Lee, replaced the Surgeon General as head of PHS.

From the optimistic days of the Civil Rights Act of 1964, the War on Poverty, and Medicare, PHS entered into an era characterized by more complicated bureaucratic maneuvering, increased public involvement, and renewed efforts to control Federal health expenditures.