C. Everett Koop, who served as United States Surgeon General for seven years in the ’80s, has died. He was 96 years old.

Koop was well-known for his stance on smoking and spoke out against the widespread use of cigarettes in the U.S. in the ’80s, bringing a very controversial topic to the forefront of conversation. He was also very involved in spreading knowledge about HIV/AIDS during his years of service, getting a public mailing out about the epidemic in a brochure which reached over 107 million people. His outspoken views on the dangers of tobacco, however, earned him accolades from those who had been trying to get their voices heard on the subject for years.

“That was the shot heard around the world, and it began to change public policy everywhere,” said John Seffrin, chief executive officer of the American Cancer Society.

Koop was a pediatric surgeon before taking on the role of Surgeon General and was highly regarded in his field as a man who never backed down from doing what he believed was right.

“Dr. Koop was not only a pioneering pediatric surgeon, but also one of the most courageous and passionate public health advocates of the past century,” said Dr. Wiley W. Souba, dean of Dartmouth’s medical school. “He did not back down from deeply rooted health challenges or powerful interests that stood in the way of needed change. Instead, he fought, he educated, and he transformed lives for the better.”

Koop was also the author of over 200 articles and books and even won an Emmy for a series he did on health-care reform.