He was a leading figure associated with presuppositional apologetics and was chairman of the Philosophy Department at Butler University for 28 years.
Clark was raised in a Christian home and studied Calvinist thought from a young age.
In 1924, he graduated from the University of Pennsylvania with a bachelor's degree in French and earned his doctorate in Philosophy from the same institution in 1929.
He began teaching at the University of Pennsylvania after receiving his bachelor's degree and also taught at the Reformed Episcopal Seminary in Philadelphia.
After his retirement from Butler in 1973, he taught at Covenant College in Lookout Mountain, Georgia, and Sangre de Cristo Seminary in Westcliffe, Colorado.
When the RPCES became part of the Presbyterian Church in America in 1982, Clark refused to join the PCA and instead entered the unaffiliated Covenant Presbytery in 1984.