Served on the Iowa Supreme Court from January 1, 1943, following his election until he resigned December 31, 1952. For nine months he was Chief Justice.
Born in Iowa County, Iowa, September 23, 1877. In 1881 the family moved to Audubon County. He was graduated from Drake University Law Department in 1904 and began the practice of law in Audubon County. He previously had served as Mayor of Audubon and County Attorney and was a member of the House of Representatives of the Thirty-seventh and Thirty-eighth General Assemblies and of the Senate in the Thirty-ninth, Fortieth and Fortieth Extraordinary Sessions. In 1925 he was appointed Judge of the then Fifteenth Judicial District where he continued to serve until commencing his service on the Supreme Court Bench.
Justice Mantz died at Audubon November 14, 1958.