The "My Best Friend's Wedding" actor will have a season-long arc as Fiona's (Emmy Rossum) new love interest Sean Pierce, an ex-bad boy and recovering addict who is her new manager at Patsy's Pies. Their relationship turns flirtatious and, as tension grows, they struggle to overcome their weakness for each other. According to Hitfix.com, Mulroney will effectively fill the role played by Jeffrey Dean Morgan in the Season 4 finale.
He joins Justin Chatwin, who will rejoin the show's cast for the upcoming fifth season, reprising his role as con man Jimmy/Steve. Fiona's ex-boyfriend, who now goes by Jack, was presumed dead after the Season 3 finale, but was seen driving past the Gallagher's home during the closing moments of last season's finale.
The series recently received three Emmy nominations in the comedy category after competing as a drama for its first three seasons, including acting nods for William H. Macy and Joan Cusack. However, the move sparked some controversy.
"There's an arbitrariness to all of it," Showtime's president of programming David Nevin recently said at the annual Television Critics Association press tour when reporters asked about the process, according to Variety. “Any category you do, I’m going to try to defy it. That’s what we do at Showtime.”
He added, "If you ask Bill Macy, he’s giving a comic performance. That’s how he defines his performance, even though it’s an incredibly dark character. It’s a lively time in television. I consider that a good thing.”
"Shameless" also stars Ethan Cutkosky, Emma Greenwell, Shanola Hampton, Steve Howey, Emma Kenney, Cameron Monaghan, Jeremy Allen White and Noel Fisher.
Mulroney, 50, was recently seen alongside Meryl Streep and Julia Roberts in the film "August: Osage County," which was adapted for the big screen by "Shameless" showrunner John Wells. His other TV credits include HBO's "Enlightened," NBC's short-lived drama "Crisis" and "New Girl" on Fox.
"Shameless" returns for Season 5 in 2015 on Showtime.
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