The U.S. Attorney for the Northern District of Illinois is now a father.
Conor Patrick Fitzgerald was born Dec. 21 to Jennifer Fitzgerald and Patrick J. Fitzgerald.
Spokesman Randall Samborn said the privacy-minded Fitzgeralds won't be releasing any further details but "everybody is happy and well."
The 49-year-old Fitzgerald, a New York native, has been U.S. attorney in Chicago since 2001.
Fitzgerald has gained a reputation as a tough prosecutor. He has sent convicted terrorists, mobsters and crooked politicians to prison.
Fitzgerald prosecuted former Vice President Cheney's top aide, I. Lewis "Scooter" Libby, for perjury and other offenses in Washington's CIA leak case.