Janowitz's character notably disclosed the homosexuality of Vito Spatafore (Joe Gannascoli), one of Tony Soprano's (James Gandolfini) best-earning captains.
In 2009, Janowitz joined the ensemble cast of Ang Lee's Taking Woodstock and wore a blonde wig and mustache to play Chip Monck, the festival's production designer.
The film explores the life and trial of Leo Frank, an American-born Jew who was lynched in Marietta, Georgia, on August 17, 1915, after being accused of the murder of a 13-year-old girl who worked in his pencil factory.
He played a comedian in "The Good News" episode of Mad Men in 2010 where he razzes the audience members: Don Draper (Jon Hamm) and Lane Pryce (Jared Harris).
In 2014, Janowitz played the character, Alex, in the film H. directed by Rania Attieh and Daniel Garcia set in Troy, NY.
He also appeared in the Broad City episode, "Destination Wedding" where he proclaimed to Abbi Jacobson that Penn Station was a “dealbreaker”.
In 2016, Janowitz portrayed Steve, in the film Little Boxes, which follows a family moving from the city life of Brooklyn to a small town in Washington state.
In the episode "Hog Day Afternoon" (2017) Janowtiz gives Gordon (Ben McKenzie) a tip, saying he retrieved pigs from a butcher and left them for a man known as the "Professor".
Janowitz took the role of mentor in the character, Tony, a manager of a bowling alley in the coming-of-age story, CRSHD (2019).