Stephenson, who holds the rank of minister counselor in the career Senior Foreign Service, joined the Department in 1985. She began her career in Panama, serving first as an economic officer and then as a political officer. Other early career assignments included desk officer for the UK, political-military officer in South Africa, and political officer in The Hague and San Salvador. 

 

Stephenson then served as special assistant to Under Secretaries for Political Affairs Peter Tarnoff and Tom Pickering, covering European affairs, including the Balkans. 

 

From 1998-2001, she served as consul general and chief of mission in Curacao, where she was responsible for the five islands of the Netherlands Antilles as well as Aruba.

 

Stephenson served from 2001-2004 as American consul general in Belfast, Northern Ireland, where she worked on the Northern Ireland Peace Process. After that, she was director for planning in the Office of the Coordinator for Reconstruction and Stabilization in the Department of State, followed by her duty as deputy senior advisor to the Secretary of State and deputy coordinator for Iraq at the State Department.