Arlen is the son of a prominent Armenian-American writer, Michael Arlen. Michael J. grew up in England and went to a boarding school in France prior to the outbreak of World War II. As a result of the war, Arlen's family moved to the United States and he became an American citizen at the age of 21. He attended Harvard University (1948-1952), after which he worked as a reporter for Life from 1952 to 1956.
He is the author of Living Room War, a book on the portrayal of the Vietnam War and American social culture by the mass media. He is also the author of Exiles and the critically acclaimed Passage to Ararat, both of which are autobiographical narratives of Arlen's Armenian ancestry. Parts of Exiles and all of Passage to Ararat originally appeared in the New Yorker.