He later joined the U.S Foreign Service, overseeing posts as Director of the Bureau of African Affairs’ Economic Policy Staff in Washington D.C. and overseas posts in the U.S. Embassies in Côte d’Ivoire and Zimbabwe.

He served as Chief of the Economic Office, American Institute in Taiwan (AIT) and worked in the Trade Unit in the U.S. Embassy in Beijing China.

He was involved in negotiations that led to China's and Taiwan's accessions to the World Trade Organization (WTO).

[2] Wall resides in Virginia and was appointed as United States Ambassador to Chad by President George W. Bush on May 12, 2004.

[1] Wall was previously married to the former United States Ambassador to Gabon and São Tomé and Príncipe, Eunice S. Reddick.