Kazimierz A. "Casey" Siemaszko, born in Chicago on March 17, 1961, is an American actor of Polish descent. He gained prominence during the 1980s through iconic roles in highly successful films, playing characters such as 3-D in the *Back to the Future* franchise (1985-1989), Billy Tessio in *Stand by Me* (1986), and Charley Bowdre in *Young Guns* (1988). His career continued with appearances in films such as *Of Mice and Men* (1992) and *The Phantom* (1996), alongside a prolific television career, with recurring roles in acclaimed series such as *NYPD Blue* and *Damages*. Siemaszko is also active as a voice actor, voicing characters in various installments of the *Grand Theft Auto* video game series. Although he has not received major individual awards, his long career has established him as a solid and versatile character actor, appreciated for his reliability on both the big and small screen.