He pastored the Moody Church in Chicago (1971–1978) and succeeded Theodore Epp as director of the Back to the Bible radio ministry.

[3] Wiersbe attended Washington High School in East Chicago, where he became a committed Christian at a Youth for Christ rally there in 1945.

During the same time frame between 1978 and 1982, Wiersbe taught practical theology classes at Trinity Evangelical Divinity School in Deerfield, Illinois and wrote the course material and taught "Imagination and the Quest for Biblical Preaching", a Doctor of Ministry course at Trinity and Dallas Seminary.

From 1980 to 1992, he went to work for the Back to the Bible radio broadcast and succeeded Theodore Epp as general director the last six years of his time there.

[1][7] Before his death, Wiersbe and his wife Betty gifted their massive personal library of over 13,000 volumes to Cedarville University in Ohio.