 After being accepted into the foreign service, Mushingi served a series of domestic and overseas assignments including Kuala Lumpur, Malaysia; Maputo, Mozambique; Lusaka, Zambia; Casablanca, Morocco; and tours in Washington D.C. in the Bureau of Intelligence and Research; the Bureau of International Organization Affairs and the Bureau of Human Resources.From 2003 to 2006, he served as the management officer assigned to travel with Deputy Secretary of State Richard Armitage, and from 2006 to 2009, Mushingi worked as management counselor of the U.S. Embassy in Tanzania.In 2009, he was promoted to Deputy Chief of Mission, and served as chargé d'affaires for the U.S. Embassy in Addis Ababa, Ethiopia.