Michael Jonathan Zegen born February 20 1979 is an American actor He is best known for his roles in the television series Rescue Me 20042011 Boardwalk Empire 20112014 and The Marvelous Mrs Maisel 20172023 Zegen was born to a teacher mother and a lawyer father and lived in Glen Rock New Jersey before moving to nearby Ridgewood when he was five He has two brothers He is Jewish His mother was born in Austria in a displaced persons camp and his maternal grandparents were Holocaust survivors from Ukraine and Poland He attended Ridgewood High School where he was active in the schools theater program Zegen is a 2001 graduate of Skidmore College His role on Rescue Me began as a recurring character in seasons 13 playing the nephew of series lead Tommy Gavin Denis Leary In seasons 56 he was promoted to the main cast when his character began probationary firefighter school to become a firefighter In 2010 Zegen was cast as gangster Bugsy Siegel for the second third and fifth season of the HBO series Boardwalk Empire In 2011 Zegen along with James Ransone was cast in supporting roles in the HBO comedy series How To Make It In America In mid2011 Zegen was cast in a recurring guest role in the second season of the AMC series The Walking Dead In 2014 he created the role of Liam offBroadway in the dark comedy Bad Jews Zegan made his Broadway debut in A View from the Bridge in 2015 In 2017 Zegen played Joel Maisel in The Marvelous Mrs Maisel For the role he has won two Outstanding Performance by an Ensemble in a Comedy Series awards from the Screen Actors Guild He returned to Broadway in 2021 to star in Trouble in Mind by Alice Childress