From training camp Kaltenborn wrote articles for the Merrill Advocate, becoming editor of the paper following his demobilisation.

His vast knowledge of foreign affairs and international politics amply equipped him for covering crises in Europe and the Far East in the 1930s.

In Augst 1932, Kaltenborn, along with Karl Von Wiegand of Hearst News and Louis Lochner of the Associated Press, interviewed Adolf Hitler.

As authors Christopher H. Sterling and John M. Kittross wrote,[citation needed] Kaltenborn reported on the Spanish Civil War "while hiding in a haystack between the two armies.

Much of what listeners heard was Kaltenborn speaking without script even after sometimes having been up for most of a night covering the breaking news.

On election night in 1948, he and Bob Trout, a former CBS colleague, were at the NBC news desk to broadcast the returns of the White House race between President Harry S. Truman and challenger Thomas E. Dewey.

As evening turned to early morning, Kaltenborn retracted his original projection and announced Truman as the winner.

He said, "I'd take some bats and balls and gloves and sneak them behind the Iron Curtain and teach them Rooshin kids how to play baseball.

Though Kaltenborn left full-time broadcasting in 1953, he provided analyses during NBC's television coverage of the Republican and Democratic conventions in 1956.

Those live newscasts were anchored by Chet Huntley and David Brinkley in their first on-air pairing.

Forever the radio newsman, Kaltenborn would report everything, including the movements of the subject he was describing, despite the fact that millions of people were watching it.

Kaltenborn was also a regular panelist on the NBC television series Who Said That?, in which a panel of celebrities attempt to determine the speaker of a quotation from recent news reports.

Returning to the United States in January 1908, Kaltenborn met the 20-year-old Olga von Nordenflycht, the American-born daughter of the German Consul General based in Chicago.

Following his graduation from Harvard and rejoining The Brooklyn Eagle, the couple returned to Berlin in 1910 for their marriage and a honeymoon tour of Europe.