Schantz was born on October 9, 1819 in Bavaria, Germany. He moved with his family to the United States in 1828, settling in Oneida County, New York. After living for a time in Oswego County, New York, the family moved to Washington County, Wisconsin in 1846. Schantz later lived in Addison, Wisconsin and Oak Grove, Dodge County, Wisconsin. In 1848, he married Catharine Schwartz, who was also a native of Bavaria. They had four children. He moved to Schleisingerville, Wisconsin (now Slinger) in 1874. Schantz died in 1879.
Schantz was elected Justice of the Peace in what is now Hartford, Wisconsin in 1846 and Register of Deeds of Washington County in 1852. He served two terms in the Assembly before serving in the Senate from 1868 to 1874. Schantz was a Democrat.