Casey Siemaszko

Casey Siemaszko
Born	Kazimierz Andrew Siemaszko 3/17/1961
Birthplace	Chicago, Illinois, U.S.
Nationality	American
Occupation	Actor
Known for	Back to the Future; Stand by Me; Three O'Clock High; Young Guns
Education	DePaul University

Kazimierz Andrew "Casey" Siemaszko (born March 17, 1961) is an American actor who came of age on screen during the 1980s, appearing in a string of films that have since become touchstones of that decade's popular cinema. He is recognized for supporting performances in Back to the Future (1985), Stand by Me (1986), and Of Mice and Men (1992), as well as for the leading role of Jerry Mitchell in the high school comedy-thriller Three O'Clock High (1987). He also played Charlie Bowdre in the Western Young Guns (1988) and starred opposite Burt Reynolds in the Bill Forsyth crime caper Breaking In (1989). A native of Chicago and a graduate of DePaul University's theater program, Siemaszko built a career that has spanned more than four decades and moved between film, television, and stage work. He is the brother of actress Nina Siemaszko.

Early Life

Siemaszko was born Kazimierz Andrew Siemaszko on March 17, 1961, in Chicago, Illinois. He was raised in the Chicago area in a family of Polish heritage; his given name, Kazimierz, is the Polish form of Casimir, and the family name reflects those roots. He has a younger sister, Nina Siemaszko, who also became a professional actress and is known for her work in film and television, including the NBC drama The West Wing.

Both Siemaszko siblings developed an early interest in acting while growing up in Chicago, and both went on to train in the city's theater scene before establishing screen careers. In interviews, Siemaszko has described his upbringing in Chicago as central to his identity as a performer, and he has continued to be associated with the Chicago acting community throughout his career.

Education

Siemaszko studied theater at DePaul University in Chicago, where he trained at the Theatre School (formerly the Goodman School of Drama). The conservatory program provided classical actor training that emphasized stage technique, and DePaul has long been a feeder school for Chicago's professional theater scene as well as for film and television careers based in Los Angeles and New York. Siemaszko began working professionally shortly after completing his training, with his first credited screen role appearing in 1983. His sister Nina later studied at the same institution, a path that contributed to the family's continuing ties to Chicago theater.

Career

Early roles and 1980s breakthrough

Siemaszko began his on-screen career in the early 1980s, with his first credits appearing in 1983. His earliest visible role for a wide audience came in Robert Zemeckis's Back to the Future (1985), in which he played Three-Fingered Joe (3-D), one of the high school bullies who accompany Biff Tannen, the antagonist played by Tom Wilson. Although the part was a supporting one, the film's enormous commercial success placed Siemaszko in one of the most recognizable ensembles of 1980s American cinema and led to further work in youth-oriented projects.

In 1986, he appeared in Rob Reiner's coming-of-age drama Stand by Me, adapted from the Stephen King novella The Body. Siemaszko played Billy Tessio, one of the older teenagers whose conversation overheard by the film's young protagonists sets the story in motion. The film became a critical and commercial success and is regularly cited as one of the defining American films of its decade.

Three O'Clock High and leading roles

In 1987, Siemaszko took on his most prominent leading role to that point, playing Jerry Mitchell in Phil Joanou's Three O'Clock High. The film follows a mild-mannered high school student who is challenged to an after-school fight by a menacing new transfer student and spends a single school day trying to find a way out. Siemaszko's performance carried the film, which used stylized cinematography and a score by Tangerine Dream to elevate a familiar high school premise. Though it underperformed on initial release, Three O'Clock High has since been reappraised as an unheralded entry in the 1980s teen comedy canon, with later writers crediting Siemaszko's everyman performance as the heart of the picture.

He followed Three O'Clock High with a role in Christopher Cain's Western Young Guns (1988), playing Charlie Bowdre alongside an ensemble that included Emilio Estevez, Kiefer Sutherland, Charlie Sheen, Lou Diamond Phillips, and Dermot Mulroney. The film dramatized the exploits of Billy the Kid and the Lincoln County Regulators, and it became a substantial box-office success, spawning a 1990 sequel and remaining a touchstone of the late-1980s revival of the Western genre. In 2026, the surviving lead cast — including Siemaszko — was announced as guests at FAN EXPO Dallas for a rare public reunion to mark the film's continuing following.

Breaking In and turn-of-the-decade work

In 1989, Siemaszko co-starred with Burt Reynolds in Breaking In, a crime comedy directed by Bill Forsyth (Local Hero, Gregory's Girl) from a screenplay by John Sayles. Siemaszko played Mike Lefebb, a young, aimless drifter who is taken on as the protégé of Reynolds's veteran safecracker. The film offered Siemaszko one of his largest screen roles to that point, and it gave him an extended two-hander with Reynolds. Forsyth later reflected on the production and on Reynolds's commitment to the role, recalling the collaborative working relationship that developed on set among the lead actors. While Breaking In did not become a commercial hit, it received favorable reviews and is generally regarded as a strong example of Forsyth's American-period work.

1990s film and television

In the 1990s, Siemaszko continued to work in supporting roles in studio films and on television. He appeared in Gary Sinise's 1992 film adaptation of John Steinbeck's Of Mice and Men, in which Sinise and John Malkovich played George and Lennie; Siemaszko took the role of Curley's antagonistic ranch hand contemporary, contributing to an ensemble cast that drew strong reviews. Other 1990s film credits included Milk Money (1994) and a range of independent productions, while he also took on guest and recurring parts on episodic television.

During this period, Siemaszko maintained ties to the Chicago theater community and gave interviews discussing the balance between Los Angeles-based film work and stage projects in his home city. He has periodically returned to Chicago for theater engagements, sometimes appearing in productions alongside his sister Nina.

2000s to present

Siemaszko has continued to work steadily in the 2000s and beyond, primarily in character roles in film and television. His later credits span procedural dramas, independent features, and television movies, with appearances documented across multiple decades of catalog listings. The continuing interest in his 1980s filmography — particularly Back to the Future, Stand by Me, Three O'Clock High, and Young Guns — has kept him a recognizable figure on the convention circuit and in retrospective coverage of the period's cinema.

Personal Life

Siemaszko is the older brother of actress Nina Siemaszko, who has worked extensively in film and television, including a recurring role on The West Wing. The siblings have spoken in interviews about their shared Chicago upbringing, their training in the city, and occasional collaborations on stage productions there. Siemaszko has generally kept his private life out of the press and has not been the subject of extensive tabloid coverage; published profiles have focused on his work and his ties to Chicago rather than on personal relationships.

Recognition

Siemaszko's most enduring recognition has come from the continuing cultural presence of the 1980s films in which he appeared. Back to the Future became a global phenomenon and remains the subject of retrospective coverage that revisits its full cast, including Siemaszko's role among Biff Tannen's gang. Stand by Me has been similarly canonized as a defining coming-of-age film of its era.

Three O'Clock High, although a commercial disappointment on initial release, has been the subject of critical reappraisal, with later writers describing it as an "unheralded" 1980s high school film whose central performance by Siemaszko anchors the picture. Young Guns has retained an active fan base, leading to the 2026 announcement of a cast reunion at FAN EXPO Dallas featuring Siemaszko alongside his co-stars Emilio Estevez, Kiefer Sutherland, Charlie Sheen, Lou Diamond Phillips, and Dermot Mulroney — an event positioned by organizers as a rare public gathering of the surviving leads. Breaking In has been re-examined by critics and filmmakers, including its director Bill Forsyth, as an overlooked late-career achievement for Burt Reynolds and a showcase for Siemaszko's work opposite him.

Siemaszko's name and career are catalogued in major library and bibliographic authority files, including the Library of Congress, the Bibliothèque nationale de France, the German National Library, and the Polish National Library, reflecting his standing as a documented figure in international film reference resources.

Legacy

Siemaszko occupies a distinctive niche in American screen acting of the 1980s and 1990s: a versatile character actor whose face is familiar from several films that have since become cultural reference points, even when his name has remained less widely known than those of the leads he supported. His presence across Back to the Future, Stand by Me, Three O'Clock High, Young Guns, Breaking In, and Of Mice and Men places him in a string of films associated with the decade's most durable directors and ensembles, from Robert Zemeckis and Rob Reiner to Bill Forsyth, Phil Joanou, and Gary Sinise.

Critics revisiting Three O'Clock High have argued that the film's reputation as a sleeper depends largely on Siemaszko's grounded leading performance, which gives the increasingly stylized narrative its emotional center. His pairing with Burt Reynolds in Breaking In has been highlighted by Forsyth and others as an example of effective intergenerational casting, helping to reframe Reynolds's late-career range while giving Siemaszko one of his fullest screen roles.

Beyond individual films, Siemaszko's career also illustrates a particular path in American acting: training at a Chicago conservatory, moving into film work without becoming a tabloid figure, and sustaining a multi-decade career through character work in both Hollywood productions and independent and television projects. Together with his sister Nina Siemaszko, he is part of an acting family with continuing ties to the Chicago theater community. The recurring retrospectives, anniversary coverage, and convention appearances built around the films of his youth — most recently the 2026 Young Guns reunion — suggest that his 1980s work continues to find new audiences four decades after its release.