Kroon began reporting as a foreign correspondent for "Time" magazine in 1953 following his expulsion from Indonesia. He was based in Geneva, Switzerland, during this time and also reported for Dutch news media outlets while at "Time". Kroon reported on several important conflicts for "Time" magazine. Kroon covered the 1956 Soviet invasion of Hungary and the 1968 Prague Spring uprising. He also reported from the Belgian Congo as the colony gained its independence from Belgium in the early 1960s.