He also served in the executive offices of Secretaries of State John F. Kerry and Hillary Clinton.

He was also a visiting lecturer at Dartmouth College for many years and taught at Howard University, before being hired as an instructor at the U.S. State Department's Foreign Service Institute.

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.

From 2011 to 2013, he served in the Executive Offices of Secretary of State Hillary Clinton and later John Kerry.

The nomination was withdrawn by President Donald Trump, who subsequently renominated Mushingi to the same position.