Background
Mertz was born on August 15, 1890 in Milwaukee, Wisconsin, where he attended a parochial school.
Mertz was born on August 15, 1890 in Milwaukee, Wisconsin, where he attended a parochial school.
During World War I, he served in the United States Army. Mertz was first elected to the Assembly in 1948. Additionally, he was a delegate to the 1952 Democratic National Convention.