On television, he is noted as a recurring cast member on Boardwalk Empire who portrayed real-life bootlegger George Remus, for appearing on Billions, and as Errol Childress in the first season of the crime drama True Detective.
He also starred as Chechen mob boss, Goran Pazar in the HBO black comedy series Barry (2018–2022).
Fleshler was born to a Jewish family[1] and studied acting at New York University's Tisch School of the Performing Arts, from which he has an MFA.
More recently, he has appeared in such films as Blue Jasmine (2013), A Most Violent Year (2014), God's Pocket (2014), The Rendezvous (2016) and Joker (2019).
Fleshler's Broadway credits include Death of a Salesman, Guys and Dolls, Arcadia, and The Merchant of Venice.