Frederick Seitz, who died Sunday at 96, was a groundbreaking scientist who led the Rockefeller University for a decade beginning in 1968.

A pioneer of solid-state physics whose work in the 1930s helped lay the groundwork for the transistor, Seitz also contributed to atomic bomb research during World War II. After the war, he became an outspoken advocate of nuclear development, including the hydrogen bomb and also defensive measures.

Switching from research to administration, he served as president of the National Academy of Sciences from 1962–1969. In the 1980s, he became chairman of the Strategic Defense Initiative Advisory Board.

More recently, Seitz became one of the best-credentialed scientists calling global warming into question and was thus a lightning rod in the debate.

Seitz grew up in San Francisco, where he was born on July 4, 1911, to a German immigrant baker. At his father’s urging, Seitz at first studied biochemistry at Stanford University, but later focused on physics and mathematics. As a Ph.D. candidate in physics at Princeton University, he and his teacher, Eugene Wigner helped lay the groundwork for solid-state physics that would lead to transistors and other electronics. In 1940, Seitz published “The Modern Theory of Solids,” based on his lectures and written by his wife, Elizabeth Marshall, a Cornell-trained physicist. In 1943, he published the authoritative text, “The Physics of Metals.”

After receiving his doctorate in 1934, Seitz held several academic appointments and also was a research physicist at General Electric Laboratories. During World War II, he helped the Army develop armor-piercing bullets and later was recruited by his mentor Wigner to help with design problems on the atomic bomb. At the end of the War, Seitz was recruited by the Army to help interview German scientists with knowledge about nuclear physics. Seitz warned of the hydrogen bomb’s destructive power, but he felt compelled to work on it.

“I feel it would be highly immoral not to do the best we can to preserve the state in which [Western] ideals represent the principal goal,” he wrote in the Bulletin of Atomic Scientists in 1950. During the Kennedy administration, he supported the resumption of atmospheric testing after the Soviet Union unilaterally broke an international moratorium.

By then, Seitz had been at the University of Illinois for a decade in a variety of posts, including head of the physics department and dean of the graduate department. He had also headed the National Academy of Sciences from 1962, and in 1965 he became the organization’s first full-time president.

A trustee of Rockefeller University from 1966, Seitz in 1968 succeeded Detlev Bronk as the university’s president. Bronk had transformed a research institute into a teaching institution that awarded solely Ph.D. degrees. Operating in an era of somewhat limited resources, Seitz managed to oversee the creation of basic research programs in biology and the establishment of a field research center in Millbrook, N.Y.

In 1984, Seitz joined Robert Jastrow and William Nierenberg to found the George C. Marshall Institute, an institution devoted to science and public policy, in Washington, D.C. It was from that post that Seitz. as well as Jastrow, who died in February, supported the Strategic Defense Initiative and expressed doubts about global warming. In a 1998, he proclaimed support for a petition said to be signed by 15,000 scientists urging the government to reject the Kyoto Protocol. Congress never did ratify the treaty, but the National Academy of Sciences took the unusual step of publicly dissociating itself from Seitz’s campaign.

Seitz was a member of the Council on Foreign Relations, and he served as a science advisor to NATO and on the President’s Science Advisory Committee. He was the recipient of more than 30 honorary doctorates, as well as, in 1973, the National Medal of Science for contributions “to the foundation of the modern quantum theory of the solid state of matter.”

In 1994, Seitz published “The Science Matrix,” a history of the rise of the scientific method.

In a 1997 interview posted on the George C. Marshall Institute Web site, Seitz was asked whether physics undermined or supported faith in God. He replied, “We are immersed in a mystery so great that it’s utterly beyond me. Clearly, something quite big is going on that we are not as yet and may never be privy to.”

Seitz is survived by his son, Joachim Seitz, three grandchildren, and four great-grandchildren.