He was a professor of New Testament at the Interdenominational Theological Center and Fisk University, and a bishop of the Christian Methodist Episcopal Church in Mississippi and Louisiana.

[3][4][5] Johnson served on the Faith and Order Commission of the World Council of Churches.

[6] In The Soul of the Black Preacher, he argued that Christianity was a liberating factor for African Americans.

[2][4] Johnson was the second African American to serve board of trust of his alma mater, Vanderbilt University, from 1971 to 1979.

[6][8] In 2018, his portrait by Simmie Knox was added to Kirkland Hall, the administration building.