Gene A. Cretz hails from Albany, New York, graduated from Albany High School, and attended the University of Rochester, graduating in 1972 with a degree in English Literature.  He also has a Master's of Science Degree in Linguistics from the State University College at Buffalo (1975).

 Cretz served as a Peace Corps Volunteer in Kabul, Afghanistan (1975-77) before joining the Foreign Service in March 1981.  His first tour was as a general services officer and consular officer at the United States Embassy in Islamabad, Pakistan (1982-84). That was followed by a year in the Operations Center and one year as an NEA staff assistant.

From 1986-88, he was a political officer in Damascus, Syria, followed by a tour as a political officer in New Delhi, India (1988-91). After India, Cretz served in Tel Aviv (1991-94) where he was responsible for the Arab affairs portfolio, including the Gaza Strip. He then returned to Washington in IO/UNP as the officer responsible for Middle East Affairs at the UN.

From 1998-01, he served in Beijing, China, where he was in charge of China's External Affairs portfolio.In 2001, he transferred to Cairo, Egypt where he served as Minister-Counselor for Economic and Political Affairs. He returned to Damascus in August 2003 and served as Charge d'Affaires until January 2004before assuming duties as Deputy Chief of Mission (DCM). In August 2004, he took up duties as the DCM in Tel Aviv.

On July 11, 2007, President Bush nominated Cretz to be the United States Ambassador to Libya and he was confirmed by the Senate on November 20, 2008. After serving in Tripoli (2008-2012), Cretz served as Ambassador to Ghana (2012-2015). From August 2015-December 2019, he was the representative of the Director General of the Multinational Force and Observers (MFO) in Tel Aviv.