Timothy McDermott was born in St. Helens, Lancashire, England, in 1926 and studied science at Liverpool and Cambridge universities. In 1947 he joined the Dominican Order and after studies in philosophy and theology at Oxford taught theology there at Stellenbosch in South Africa. During this time he collaborated in the sixty-volume translation of the Summa Theologica published in the 1960s, editing the volume on God’s nature and existence, and he wrote many theological articles and a book on the Apostles' Creed.

From 1970 to 1986, McDermott taught and researched the theory of computer languages and artificial intelligence at the universities of London, Cape Town, and Tasmania.

While working on Summa Theologiae: A Concise Translation he was a visiting Fellow at St. Edmunds College, Cambridge, and was a visiting associate professor at the University of Illinois at Urbana-Champaign.