He created, produced, and starred in the comedy series "The Gentlemen's League" for the Audience Network in 2010, which followed the real-life fantasy football league he ran with actor Jerry Ferrara. Greenfield had his feature film debut in the film "Cross Bronx". Greenfield had a featured role in "When Do We Eat?", as an Internet tycoon who, after losing his fortune, becomes a Hasidic Jew. In 2011, Greenfield began playing the role of Schmidt in the sitcom "New Girl". The role earned him nominations for both a Primetime Emmy Award for Outstanding Supporting Actor in a Comedy Series and a Golden Globe Award for Best Supporting Actor – Series, Miniseries or Television Film.