He was also an activist on issues relating to African politics, for example United States Government disinvestment from South Africa during Apartheid.
[5] In 1970, Johnson published the book The Cameroon Federation: Political Integration in a Fragmentary Society, the basis of which was his PhD dissertation.
[9] This system was of particular interest because Cameroon was an officially bilingual nation with both French and British colonial histories, and the country had recently voted to unify after 40 years of administrative and cultural division.
[12] During the 1960s and 1970s, Johnson was a member of the Africa Policy Task Force for the George McGovern 1972 presidential campaign and the Foreign Affairs Study Group of the Democratic Party Advisory Council,[3] as well as UNESCO's U.S. National Committee.
As president of the TransAfrica Boston Support Group in 1982, he has been credited with playing an important role in the passage of divestment legislation by the Massachusetts House of Representatives, overriding a veto by Governor Edward J.
[16][17] For the remainder of his academic career Johnson continued to study institutional development and international relations, with a particular focus on Africa.