At age 15 he entered the monastery of the Augustinian Order of Regular Canons, where he studied Aristotle, languages and divinity.
Even after Vermigli’s forced flight in 1542, Zanchi remained as a teacher of Greek at the monastery school.
After a brief stay in Geneva, he wanted to go to England, but was called to Strasbourg and worked there as a professor of the Old Testament at the college of St. Thomas.
The demand for Strasbourg faculty and pastors to commit themselves to the Augsburg Confession created difficulties for him.
When Calvin chided him for his equivocation, Zanchi went public with his views again causing the controversy to erupt anew.
Zanchius was a voluminous writer whose works include Confession of the Christian Religion and Observation on the Divine Attributes.
Zanchi argues that natural law should be seen as moral knowledge that God has universally and directly “reinscribed” on the human mind after the Fall, rather than as a "relic of the original image of God” or some “essential part of human nature.
How good and great he was, how formed to shine, How fraught with science human and divine; Sufficient proof his numerous writings give, And those who heard him teach and saw him live.