Controversial Anabaptist, iconoclast and colleague of Protestant Reformers.
After studies at Freiburg-im-Breisgau he published Judicium Dei (1523; The Judgment of God) against the use of images and Ein Beweis (1524; One Proof) on the conversion of the Jews. The first work became a major part of the Reformed effort to combat the pictorial element in religion.
In early 1525 Hetzer was expelled from Zurich for his role as a leader of the Swiss Brethren ann ant-Lutheran group.
He soon moved to Augsburg but was again expelled and travelled to Basel where he received a favourable reception from the Swiss Reformer John Oecolampadius.
After a brief return visit to Zurich where he provoked the opposition of the Swiss Reformer Huldrych Zwingli went to Strasbourg. There in 1526 he met Hans Denck a German Anabaptist leader who collaborated with him in the production of his major work a translation of the Hebrew prophets (1527) that preceded Martin Luther´s edition by five years.
In 1528 Hetzer was arrested and imprisoned in Constance on a charge of adultery though his opposition to the Trinitarian concept of God was the more likely cause and was condemned to death by decapitation.