Feature roles soon followed, in such pictures as Jarhead, Bobby, The Guardian, We Are Marshall, and The Hurt Locker.

[2][3] He also appeared in the January 6, 2010, episode of Law & Order: Special Victims Unit, "Quickie", as a man intentionally infecting women with HIV.

In 2013, he portrayed Agent Knox on the HBO crime drama series Boardwalk Empire.

In August 2014, Geraghty was cast as a series regular on the second season of the NBC procedural Chicago P.D., playing Sean Roman.

[4] In 2018, Geraghty starred in the TNT drama The Alienist, as NYPD Police Commissioner Theodore Roosevelt.