Answer
Emilio Colombo held the role of Minister of Foreign Affairs for the longest time, serving in that position for a total of eight years. He was first appointed to the post in 1959 by Prime Minister Amintore Fanfani, and he served again in the same position under Prime Ministers Giulio Andreotti, Giovanni Spadolini, and Bettino Craxi. Colombo also served as Prime Minister of Italy from 1970 to 1972.