[1] Fontana was born on the west side of Buffalo, New York, and is the fourth of five children in an Italian-American family;[2] he is a cousin of actress Patti LuPone.

Fontana has been the creator/showrunner for Oz, Copper, The Jury, The Beat, The Bedford Diaries, The Philanthropist and he was also the showrunner on Homicide: Life on the Street.

Fontana wrote the HBO film Strip Search, directed by Sidney Lumet, and contributed two pieces to the September 11 special, America: A Tribute to Heroes.

Fontana also created the historical drama TV series Borgia for the French premium-pay channel Canal+, produced by Atlantique Productions and EOS Entertainment.

Fontana has written articles for such periodicals as The New York Times, TV Guide, and Esquire, and has taught at Columbia, Syracuse, Rutgers, and the State University College at Buffalo, his alma mater, from which he received the Distinguished Alumni Award and an honorary Doctorate of Letters.

He is president emeritus of the WGAE Foundation, commonly known as the Writers Guild Initiative, and serves on the boards of the Acting Company, the Williamstown Theatre Festival, DEAL, the New York City Police Museum, and Stockings with Care, among others.