[4][5][3] Karnow enrolled at the University of Iowa, but left in 1943 to serve in the Army Air Force, in which he was a weather observer, cryptographer and unit historian along the China-India border.

In 1950, he was taken on as a local "interpreter, researcher, and legman" by the Paris bureau of Time magazine, but was soon promoted to correspondent, covering France, Western Europe, and francophone North Africa.

After the war, in the 1970s and 1980s, Karnow was a columnist for King Features Syndicate, a contributor to Le Point and Newsweek International, and an editor with The New Republic.

[3] He was also a founder and editor of the International Writers Service, a non-profit agency which commissioned work from European and Japanese journalists on their own countries and made it available to American newspapers.

[9] Karnow’s first book was his text for Southeast Asia (1962), a volume in his employer's illustrated, mass-market, Life World Library series.

Both were very successful, reaching large parts of the American public at a time when interest in the war was reviving after nearly a decade of forgetting.

Like the conflict itself, the book and film were controversial and helped spark the ongoing public debate on the history and meaning of the war.

Rising political unrest in the Philippines in the 1980s, culminating in the fall of the 20-year regime of President Ferdinand Marcos, prompted Karnow's second book and television project.

[5] Unlike the academic style of his China book, Karnow's narratives on Vietnam and the Philippines combined research, reporting, and personal observations.

[16][4] In his last published book, Paris in the Fifties (1997), Karnow chronicled his years as a young reporter in Europe and North Africa, making use of his copies of dispatches that had been used mostly as background material by Time editors in New York.

[6][3] In 1959, he married Annette Kline, a widowed artist who was working at the time as a cultural attaché for the U.S. State Department in Algiers and Paris.