The complaint filed with the Police and Fire Commission accuses Chief John Thomsen of conduct unbecoming an officer. It calls for Thomsen to be disciplined or fired.
The Kenosha News says the union alleges Thomsen repeatedly engaged in inappropriate or harassing behavior against employees, including his use of homophobic slurs and abusive language.
Thomson was appointed chief in 2006. He was publicly reprimanded in 2010 by the City Council for failing to maintain objectivity in mishandling a personnel matter.
Thomson did not immediately respond to an email and phone message seeking comment.