As an Emmy nominated writer and Golden Globe winner, Renzulli has written teleplays for The Sopranos, mainly in the first two seasons, and another Emmy nominated episode in the third season of the television show. He co-executive produced the short lived 2006 television show Heist on NBC. He was a co-executive producer and writer for the Starz drama series Crash. Crash showrunner Glen Mazzara handpicked the writing staff for the series and selected people with a background of writing edgier material. Renzulli topped his list. In 2010, he played Sal LoNano, the real-life manager of "Irish" Micky Ward, in the Golden Globe and Academy Award-nominated film The Fighter. Frank Renzulli had a recurring role as the private detective Vinnie Delgato on NBC's Harry's Law. He reunited with Glen Mazzara to write a freelance episode of AMC's The Walking Dead entitled "When the Dead Come Knocking" in 2012. The episode was critically acclaimed and considered one of the best of the ongoing series.