Chicago Fire Guest cast, played by Nick Gehlfuss Episode 3x19: I Am the Apocalypse (Apr 7, 2015) Episode 4x01: Let It Burn (Oct 13, 2015) Episode 4x03: I Walk Away (Oct 27, 2015) Episode 4x04: Your Day is Coming (Nov 3, 2015) Episode 4x05: Regarding This Wedding (Nov 10, 2015) Episode 4x10: The Beating Heart (Jan 5, 2016) Episode 4x17: What Happened to Courtney (Mar 29, 2016) Episode 4x19: I Will Be Walking (Apr 19, 2016) Episode 4x20: The Last One for Mom (Apr 26, 2016) Episode 4x21: Kind of a Crazy Idea (May 3, 2016) Episode 5x02: A Real Wake-Up Call (Oct 18, 2016) Episode 5x15: Deathtrap (Mar 1, 2017) Episode 6x14: Looking for a Lifeline (Mar 22, 2018) Episode 7x02: Going to War (Oct 3, 2018) Episode 8x04: Infection, Part I (Oct 16, 2019) Episode 8x14: Shut It Down (Feb 12, 2020) Episode 8x19: Light Things Up (Apr 8, 2020) Episode 8x20: 51's Original Bell (Apr 15, 2020) Episode 9x10: One Crazy Shift (Mar 31, 2021) Episode 9x11: A Couple Hundred Degrees (Apr 7, 2021)
