Zeidler was known as the "singing Mayor of Milwaukee" because wherever he went he always had a song, especially "God Bless America", for everyone.
He was distinguishing himself in National Politics with the hope of running for President, when World War II broke out. He resigned his position as mayor and eagerly joined the Navy, asking for the most dangerous job on ship, becoming an officer in charge of a gun battery on board the merchant ship USS LaSalle. The ship and all hands were lost at sea off the Coast of South Africa in December of 1942.
Carl Zeidler was the first Democrat mayor of Milwaukee since 1906. He unseated Socialist mayor Dan Hoan, who had held office for 24 years. Carl's brother Frank P. Zeidler would later also become Mayor of Milwaukee.