Brian Timothy Geraghty (born May 13, 1974) is an American film and television actor, best known for his roles as Ronald Pergman on Big Sky, Dale on the series The Fugitive, Gene Colder on Briarpatch, Theodore Roosevelt on The Alienist, Police Officer Sean Roman on Chicago P.D., Specialist Owen Eldredge in the Academy Award-winning film The Hurt Locker, Tom Bogdan in We Are Marshall, Billy Hodge in The Guardian, and Fergus O'Donnell in Jarhead.

Filmography

• 2025The Luckiest Man in America — Ed
• 2024Red Right Hand — Sheriff Hollister
• 1923 — Zane Davis
• Gaslit — Peter
• Big Sky — Ronald Pergman
• 2020Blindfire — Will Bishop
• Briarpatch — Gene Colder
• The Fugitive — Dale
• 2019Avenues — Jack
• 2019Extremely Wicked, Shockingly Evil and Vile — Florida Public Defender Dan Dowd
• 2019Faith — Chris
• 2019The Standoff at Sparrow Creek — Noah
• 2018My Days of Mercy — Weldon
• The Alienist — Theodore Roosevelt
• Chicago Med — Sean Roman
• 2015The Stanford Prison Experiment — Executive Producer
• 2015Verbatim: The Ferguson Case — Darren Wilson
• 2015Wildlike — Uncle
• Chicago P.D. — Sean Roman
• 2014Date and Switch — Lars
• 2014Loitering with Intent — Devon
• 2014The Identical — William Hemsley
• 2013Ass Backwards — Brian
• 2013Kilimanjaro — Doug
• 201210 Years — Garrity
• 2012ATM — David Hargrove
• Chicago Fire — Sean Roman
• 2012Flight — Ken Evans
• 2012Heroes and Demons — Dan (segment "The Second Bakery Attack")
• 2012Refuge — Sam
• 2011Seven Days in Utopia — Jake
• 2010Bastard — Man
• Boardwalk Empire — Agent Warren Knox
• 2010Jake Gyllenhaal Challenges the Winner of the Nobel Peace Prize — Fergus O'Donnell (archive footage)
• 2010Krews — Henry McFarlin
• 2010Open House — David
• 2010The Chameleon — Brian Jansen
• 2010The Second Bakery Attack — Dan
• 2009Easier with Practice — Davy Mitchell
• 2008Love Lies Bleeding — Duke
• 2008The Hurt Locker — Specialist Owen Eldridge
• True Blood — Brian Eller
• 2007An American Crime — Bradley
• 2007I Know Who Killed Me — Jerrod Pointer
• 2006Art School Confidential — Stoob
• 2006Bobby — Jimmy
• 2006Conversations with Other Women — Groom
• 2006Cruel World — Collin
• 2006The Elder Son — Greg
• 2006The Guardian — Billy Hodge
• 2006We Are Marshall — Tom Bogdan
• 2006When a Stranger Calls — Bobby
• 2005Jarhead — Fergus O'Donnell
• 2002Town Diary — Young Frank Ryan
• Ed — Ari
• Law & Order: Special Victims Unit — Peter Butler, Sean Roman
• The Sopranos — Counter Boy
• Law & Order — Phillip Ludwick
• Kockroach

Appearances as themselves (1)

• 2006"Jarhead" Diaries — Self