Casey Siemaszko (born Kazimierz A. Siemaszko) is a Polish-American actor and the brother of actress Nina Siemaszko. The son of a fighter in the Polish Underground who survived the Sachsenhausen concentration camp, Siemaszko narrated the 1998 feature, The Polish-Americans. Siemaszko was a graduate of the Goodman School of Drama at DePaul University in Chicago, which his sister, Nina Siemaszko later also attended. His acting career consists of smaller roles in dozen of popular films, including Back to the Future, Young Guns, Silence of the Heart, Of Mice and Men, Killing Kennedy, Back to the Future Part II and Stand By Me.

Filmography

• Billions — Seids
• 2013Killing Kennedy — Jack Ruby
• The Blacklist — Sam Raimo
• Elementary — Michael McGee
• NYC 22 — Blume
• Person of Interest — Lester Strickland
• Unforgettable — Lt. Greg Sartain
• Blue Bloods — Josh Thorp
• 2009Public Enemies — Harry Berman
• White Collar — Bertie Slavkin
• New Amsterdam — Peter Huygens
• Damages — Detective Dan Williams
• 2007The Boy Who Cried Bitch: The Adolescent Years
• The Inside — Billy Ray Pope
• CSI: NY — Paul Sabotini
• 2004Grand Theft Auto: San Andreas - The Introduction — Johnny Sindacco (voice) (uncredited)
• 2003The Street Lawyer — Rafter Mayes
• Law & Order: Criminal Intent — Harvey Gruenwald
• 2000The Crew — Young Bobby Bartellemeo
• 1999Chameleon II: Death Match — Jake Booker
• Law & Order: Special Victims Unit — EPA Official
• 1999Limbo — Bobby Gastineau
• Storm of the Century — Alton "Hatch" Hatcher
• 1998Together and Alone — Billy
• 1997Bliss — Tanner
• Chicago Sons
• Oz — Detective Tarnowski
• 1997Rose Hill — Fergus Carroll
• 1996Mistrial — Detective Bobby Zito
• 1996The Phantom — Morgan
• 1995Black Scorpion — Dr. Goddard / The Breath Taker
• 1995Napoleon — Conan (voice)
• 704 Hauser
• 1994Milk Money — Cash
• 1994Teresa's Tattoo — Michael
• The Adventures of Brisco County, Jr. — Ned Zed
• 1993The Paint Job — Cal
• 1992Near Mrs. — Colin Phipps
• 1992Of Mice and Men — Curley
• 1991The Big Slice — Mike Sawyer
• 1991The Chase — Hutchinson
• Law & Order — Bart Rainey, Defense Attorney Shuman
• 1989Back to the Future Part II — 3-D
• 1989Breaking In — Mike Lafebb
• 1988Biloxi Blues — Don Carney
• 1988Young Guns — Charley Bowdre
• 1987American Harvest — Dakota
• 1987Gardens of Stone — Wildman
• 1987Three O'Clock High — Jerry Mitchell
• 1986Amazing Stories — Jonathan
• 1986Miracle of the Heart: A Boys Town Story — Andy Grainger
• 1986Stand by Me — Billy Tessio
• Amazing Stories — Jonathan
• 1985Back to the Future — 3-D
• 1985Secret Admirer — Roger Despard
• 1984Hard Knox — Aaron Davis
• 1984Silence of the Heart — Jeff
• 1983Class — Doug
• St. Elsewhere — Rick Messina
• The Facts of Life
• Hallmark Hall of Fame — Fergus

Appearances as themselves (1)

• 1994My Life's in Turnaround — Himself