MacPherson spent six years in the Marine Corps Reserves, starting in 1965. Working at "Time" magazine as a trainee, he was fired after throwing a drink in an editor's face while attending a holiday party. He started working for "Newsweek" magazine in 1968, first as a national correspondent, providing coverage from cities in the United States including Boston, Chicago and Los Angeles. Five years later, he started taking on overseas assignments, including covering the Yom Kippur War in 1973, the 1974 Turkish invasion of Cyprus and "The Rumble in the Jungle" in Kinshasa, Zaire in October 1974, with world Heavyweight boxing champion George Foreman facing former world champion Muhammad Ali, reporting from postings in London, Nairobi and Paris.