The son of Walter and Alice Heflin, Heflin was born in Leesburg, Virginia, but grew up in Huntsville, Alabama, graduating from Butler High School in 1976. He attended Birmingham-Southern College, earning B.A. degrees in political science and religion in 1980. He went on to law school at the University of Alabama, graduating with a J.D. in 1983.
After finishing law school, he worked as a lawyer in Huntsville and Mobile, Alabama, until 1987, when he passed the Foreign Service exam and joined the State Department. His first assignment was as vice consul in Lima, Peru, serving there until 1990 when he took a similar post in Madras, India.
In 1992, Heflin was named consul and deputy principal officer in Hermosillo, Mexico. His first African posting came in 1993 as consul in Lusaka, Zambia. He returned to the United States in 1995 as Rwanda/Burundi desk officer and in 1997 was coordination division officer in the Bureau of Consular Affairs.
Heflin was sent overseas again in 1999, this time as consul in London. He returned to Washington in 2004 as deputy director in the Office of African Regional and Security Affairs and in 2006 was deputy director in the Office of West African Affairs and served as acting director for a time.
He returned to Mexico in 2009 as the principal officer and Consul General in the border town of Nuevo Laredo. In 2012, Heflin was brought back to Washington as managing director of the Consular Affairs Visa Office, where he served until his 2015-2018 term as U.S. Ambassador to Cabo Verde.He served in Mexico City as the Minister Counselor for Consular and Consulate Affairs from 2018-2020.
MCCA Heflin speaks Spanish and Portuguese.