In 1978, he completed his ministerial training from Reformed Theological Seminary in the US before moving on to receive his PhD from the University of Wales, Lampeter, with a thesis on Calvin's preaching on the Book of Job.

[1] He has also produced a volume for the Biblical commentary series published by Banner of Truth Trust and Evangelical Press.

In 2004, Derek Thomas became editorial director for The Alliance of Confessing Evangelicals and the editor of its e-zine, Reformation 21.

They noted that "the lack of attribution resulted from unclear note-taking more than a decade before the commentary on Acts was written, and we believe it does not reflect intentional misuse on the part of the author.

'"[5] A commission of the Associate Reformed Presbyterian Catawba Presbytery found that Derek Thomas had in fact copied from the sermons of Sinclair Ferguson without proper attribution, but that "none of the interviews and investigations of this Committee have revealed any credible evidence that Derek Thomas intentionally engaged in the practice of plagiarism."