A close ally of Oppenheimer's and Vannevar Bush's, he played a central role in shaping America's atomic age, advising the Atomic Energy Commission and the Joint Research Development Board.
Conant was second only to Oppenheimer as an advisor to the government on military and civilian applications of nuclear technology.
A former secretary of the Army, he had oversight of psychological warfare strategies across multiple agencies, and he later chaired the committee that revoked Oppenheimer's security clearance.
He was briefed by Robert Oppenheimer himself, and instructed to turn the findings into a book.
Oppenheimer called it extraordinarily well informed, and it launched Kissinger into the public eye.
His invitation to the Council on Foreign Relations study group on nuclear strategy placed him alongside figures like Robert Oppenheimer and Gordon Dean.