Hager started out his career as a foreign correspondent in June 1969, reporting on the Vietnam war. He was soon assigned to NBC's Berlin bureau, where he continued to cover other foreign trouble spots, including the overthrow of the Iranian Shah in 1979 and the 1989 invasion of Panama by U.S. troops. Hager also covered four Olympic games for NBC, reporting from Germany during the Black September terrorist attacks of the 1972 Summer Olympics in Munich. In 1984, he was arrested while reporting from the Democratic National Convention in San Francisco.