After graduating from high school in Peru, Nebraska, he joined the U.S. Army, serving from 1944 to 1948 and reaching the rank of First Lieutenant.

In 1952 he was appointed as Vice Consul and deputy principal officer in Dar es Salaam, Tanganyika, where he served from 1953 to 1955.

He attended the National War College in 1969-70 and served as educational and cultural affairs officer at the State Department in 1970 and 1971.

[2] His appointment came at a time of major political and social upheaval in that country, following the Soweto uprising and the murder of student activist Steve Biko.

It also came at a time of high tension between the white minority South African government and the Carter Administration.

As U.S. envoy, Edmondson was the public face of what many conservative South African whites considered to be a hostile American government, given the U.S. government's condemnation of apartheid in South Africa and its vocal support for civil and political rights and democratic reform leading to majority rule.