His interest in cardiovascular research led him to accept the position of Chief of General Medicine and Experimental Therapeutics at the National Heart Institute in Bethesda in 1950, at first on a part-time basis while continuing his work at the Baltimore hospital.

He also served as the first Chairman of the Medical Board of the Clinical Center (1953–1955) and was concurrently instructor and then assistant professor at the Johns Hopkins University School of Medicine from 1944 to 1961.

At the end of the decade, the Royal College of Physicians in the United Kingdom appointed a committee to investigate the relationship between smoking and health.

The committee's report, issued on March 7, 1962, clearly indicated cigarette smoking as a cause of lung cancer and bronchitis and argued that it probably contributed to cardiovascular disease as well.

The report also noted out that there was suggestive evidence, if not definite proof, for a causative role of smoking in other illnesses such as emphysema, cardiovascular disease, and various types of cancer.

[1] The landmark Surgeon General's report on smoking and health stimulated a greatly increased concern about tobacco on the part of the American public and government policymakers and led to a broad-based anti-smoking campaign.

[2] Terry himself continued to play a leading role in the campaign against smoking after leaving the post of surgeon general, which he occupied through October 1, 1965.

He chaired the National Interagency Council on Smoking and Health, a coalition of government agencies and nongovernment organizations, from 1967 to 1969, and served as a consultant to groups such as the American Cancer Society.