Willis studied Greek as an undergraduate in the 1950s, but he majored in Old Testament as a graduate student. He moved to Nashville, Tennessee to teach Bible at David Lipscomb College and enrolled at Vanderbilt University. During this time he also preached for a number of churches in Texas and Tennessee. Willis wrote his doctoral dissertation on "The Structure, Setting and Interrelationships of the Pericopes in Micah." His was an early voice arguing for the unity of the book at a time when redaction critics focused more on the "authentic" fragments. He went on to be a major translator of works in Swedish and German in the field of Old Testament Studies. He authored a number of well-received commentaries on Genesis, 1–2 Samuel and Isaiah in the Living Word Commentary series as well as editing the volume on The World and Literature of the Old Testament in that series. In his retirement he continues to publish scholarly articles and books in the field of Old Testament studies. He also wrote a number of biblical studies for a popular audience. Willis made a lasting contribution through his teaching particularly within the American Restoration movement. Willis taught at David Lipscomb College in Nashville from 1966 to 1971 when he moved back to Abilene and taught for 46 years until his retirement in 2017, for a total of 61 years of teaching. At his retirement a Festchrift was published in his honor, Worship and the Hebrew Bible: Essays in Honor of John T. Willis ed.by M. Patrick Graham, Rick R. Marrs, and Steven L. McKenzie, Sheffield Academic Press.
Works
My Servants the Prophets, Vol. 1–2 . Biblical Research Press
My Servants the Prophets Vol. 3–4. Biblical Research Press
Insights from the Psalms Vol. 1–3. Biblical Research Press
Essays on Old Testament Ethics: J. Philip Hyatt, In Memoriam ed. James L. Crenshaw, John T. Willis. KTAV
The Message of Old Testament History Volume 1: Adam to Moses. Biblical Research Press
The Message of Old Testament History Volume 2: Joshua to Ruth. Biblical Research Press
The Message of Old Testament History Volume 3: Samuel to Solomon. Biblical Research Press
The Message of Old Testament History Volume 4: Rehoboam to Nehemiah. Biblical Research Press
The World and Literature of the Old Testament, The Living Word Commentary on the Old Testament, Vol 1. ed. John T. Willis, Sweet Publishing Company, ACU Press
Genesis. The Living Word Commentary on the Old Testament, Vol 2 Sweet Publishing Company, ACU Press
1 and 2 Samuel. The Living Word Commentary on the Old Testament, Vol 6. Sweet Publishing Company, ACU Press
Isaiah. The Living Word Commentary on the Old Testament, Vol 12. Sweet Publishing Company, ACU Press
Yahweh and Moses in conflict : the role of Exodus 4:24–26 in the book of Exodus. Peter Lang
Instruction shall go forth : studies in Micah and Isaiah. ed. Timothy M Willis; Mark W Hamilton, Pickwick Publications