McGantry Tip "T.I." Harris as Trey (Season 2), a former gang member with designs on a career in Chicago's City Hall Sanaa Lathan as Mona Fredricks (Season 2), Tom Kane's new chief of staff. Recurring cast Francis Guinan as McCall "Mac" Cullen (Season 1–2), Governor of Illinois, who is running for re-election Amy Morton as Catherine Walsh (Season 2), the Republican candidate for governor Nicole Forester as Maggie Zajac (Season 1–2), Ben Zajac's wife Karen Aldridge as Dr. Ella Harris (Season 1–2), Tom Kane's neurologist James Vincent Meredith as Alderman Ross (Season 1–2), an alderman serving on the Chicago City Council, from the South Side Anthony Mockus, Sr. as Mayor Rutledge (Season 1–2), Tom Kane's predecessor and Meredith's father, who is in a catatonic state Gil Bellows as Vacarro (Season 2), casino investor and Meredith's lover Doug James as the Grey Haired Man (Season 1–2), Tom Kane's enforcer Jennifer Mudge as Debra Whitehead (Season 1), caretaker / nurse to Tom Kane's father-in-law Ricardo Gutierrez as Alderman Mata (Season 1), an alderman serving on the Chicago City Council, representing the 30th ward Joe Minoso as Moco Ruiz (Season 1), the head of a construction company working on the O'Hare expansion Steve Lenz as Phone Monkey (Season 1–2), an aide to Tom Kane Danny Goldring as Ryan Kavanaugh (Season 1–2), Tom Kane's childhood friend and former homicide detective Richard Perez, as Alderman Ortiz Mary Hollis Inboden as Jackie Shope (Season 1–2), a journalist at The Sentinel working under Sam Miller Development and production Farhad Safinia developed Boss in late 2009, with creative input from Kelsey Grammer and his production company Grammnet Productions. In November 2010, the script was shopped around to various cable networks and, following a heated and contentious bidding war, Starz placed an eight episode order for the series, based solely on the strength of the script. This was in keeping with Starz's business model of not ordering pilots but rather green-lighting projects straight-to-series. Safinia wrote the pilot, Gus Van Sant was attached to the project as director, with Grammer, Safinia, Van Sant, Richard Levine, Lyn Greene, Brian Sher and Stella Bulochnikov-Stopler serving as executive producers. Casting announcements began in November 2010, with Grammer first to be cast. He portrays Tom Kane, "the Mayor of Chicago who is diagnosed with a degenerative mental condition that only he and his doctor know about". Next to join the series was Connie Nielsen