[1] In 1957, he became the first African American to earn a PhD from New College, University of Edinburgh, in philosophical theology.

[5] A festschrift was prepared in his honor entitled The Quest for Liberation and Reconciliation (2005).

[6] In the 1960s, Roberts and James H. Cone emerged as two leading figures in the black theology movement.

Roberts challenged theologians such as Jürgen Moltmann as articulating theologies that were not relevant for black people in America.

[7][8] He also criticized the early works of Cone's, namely Black Theology and Black Power (1969),[4] but also saw himself as mediating between Cone and Martin Luther King Jr.[9] Roberts was married to Elizabeth Caldwell Roberts and had four children, including the popular erotic fiction author known pseudonymously as Zane.