In 1981, two years after the establishment of the Revolutionary Islamic Republic of Iran, Mehr immigrated to the United States. There he joined Boston University as Professor of International Relations, known now as the Pardee School of Global Studies. In 1982, Mehr served as the recipient of a certificate in appreciation for the contribution of Iranians to life in the Commonwealth of Massachusetts from Governor Michael Dukakis. He retired in 1997 as Professor Emeritus.