Miguel Humberto Díaz (born September 29, 1963) is an American theologian, diplomat and commentator who served as United States Ambassador to the Holy See. He was nominated by President Barack Obama and confirmed by the U.S. Senate on August 5, 2009. He resigned on November 5, 2012, and was immediately named University Professor of Faith and Culture at the University of Dayton. He was the first Hispanic U.S. Ambassador accredited to the Holy See.
As ambassador, Díaz helped launch the Religion in Foreign Policy Working Group of the Secretary of State's Strategic Dialogue with Civil Society. The Working Group facilitates regular dialogue between the U.S. foreign policy establishment and religious leaders, scholars, and practitioners worldwide on strategies to build more effective partnerships on issues such as conflict prevention, humanitarian assistance and national security.
On May 20, 2014, Loyola University Chicago announced that they intended to hire Díaz as a pro