Pastor Calvin was born in Ohio and raised in Texas. He is the son of a lay pastor and the grandson of a vocational evangelist.

He is a graduate of Baylor University, has a Master of Divinity from Southwestern Baptist Theological Seminary and a Doctor of Ministry (D. Min.) in Expository Preaching from The Southern Baptist Theological Seminary in Louisville, KY. Pastor Calvin has served in various churches and his family also served as missionaries in Spain. He was called to Applewood as Senior Pastor in October 1999.

In addition to his ministry at Applewood, Dr. Wittman serves as a trustee at Criswell College, regularly contributes to "Open Windows," a monthly LifeWay devotional publication and has contributed sermons to Lifeway's Pastor Resources Division.