Benjamin "Ben" Rosenfield (born August 1, 1992) is an American actor and musician, perhaps best known for playing Willie Thompson on the fourth and fifth seasons of HBO's period crime drama series Boardwalk Empire (2013–14). He has starred as Tommie Scheel in the documentary film Teenage (2013), Henry Ellis in the musical drama Song One (2014), Fisher Miller in the teen drama Affluenza (2014), and Dan Mercer in the romantic drama 6 Years (2015).