Zeidler was elected Milwaukee County Surveyor in 1938 on the Progressive Party ballot line (the Socialist Party and Progressives were in coalition in Milwaukee at that time). He was elected to a six-year term on the Milwaukee Board of School Directors (a non-partisan office) in 1941, just after his brother Carl Zeidler was elected Mayor of Milwaukee in 1940. In 1942, Frank Zeidler was the Socialist nominee for Governor of Wisconsin, receiving 1.41% of the vote in a six-way race. He was re-elected to the Milwaukee School Board in 1947.