He was the founder and owner of the American Boys' Camp for indigent children at Coloma, Wisconsin, and, infamously, was also lawyer to Al Capone.

Libonati was elected as a Democrat to the Eighty-fifth Congress to fill the vacancy caused by the death of James B. Bowler.

According to Todd S. Purdum's An Idea Whose Time Has Come, Libonati's political career ended as a result of his votes during the drafting of the Civil Rights Act of 1964.

Libonati instead voted with liberal colleagues who wanted to maintain the bill's stronger provisions, even though Kennedy had spoken to Daley directly to complain about his behavior.

In a private conversation with a colleague shortly after the vote, Libonati said he had received a call from the Daley machine indicating that his political career was over.