The brother of the producer John Whitesell and the writer Christopher Whitesell, Sean Whitesell is known for working in the same fields as his siblings in addition to intermittently appearing as a television actor. Whitesell made his screen debut with a guest role on a first-season episode of "Law & Order." After performing as separate recurring characters on the prison drama "Oz" and the police procedural "Homicide: Life on the Street," Whitesell made his mark as a writer on the very same shows. He served as a writer and producer on the rabble-rousing teacher dramedy Boston Public before bringing his TV-law expertise to the unsolved-crime series "Cold Case" (2003-2010), of which he penned nine episodes and produced 62. The scribe has also written and produced installments of such series as the crime drama "The Black Donnellys" and the quirky detective show "Memphis Beat." In 2011, he reunited with the "Oz" creator Tom Fontana as one of the top writers on the period drama "Borgia," exploring the lawless depravity of the Renaissance era.