About Cillian O'Sullivan
Cillian O'Sullivan was an Irish and American actor.
Cillian O'Sullivan (born ) is an American-born Irish actor who has had roles in Then You Run (Sky 2023), Bull (CBS 2019), Vikings (History 2016), 6Degrees (BBC 2012), Single-Handed (RTÉ 2009), and Seacht (BBC/TG4 2008).
Born in New York to Irish parents, From an Irish-speaking family, won the "best narrative feature" at the 2019 San Luis Obispo International Film Festival.
In 2021, he filmed a Sky Studios series titled Then You Run, which was released in July 2023. As of 2022, O'Sullivan was reportedly working on a film titled The Lost Princess.
In 2025, O'Sullivan appeared as Devlin, an Irish gangster, in Daredevil: Born Again, and as Dr. Roger Korby in the third season of Star Trek: Strange New Worlds.
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Important facts
Related people
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Frequently asked questions
Who was Cillian O'Sullivan?
American-born Irish actor
What was Cillian O'Sullivan's occupation?
Cillian O'Sullivan was an actor.
What nationality was Cillian O'Sullivan?
Cillian O'Sullivan was Irish and American.
Sources & further reading
· Wikipedia: Cillian O'Sullivan
· DBpedia: Cillian O'Sullivan
Cite this page
APA: Biography.guide. (2026). Cillian O'Sullivan. https://biography.guide/cillian-o-sullivan/
MLA: "Cillian O'Sullivan." Biography.guide, https://biography.guide/cillian-o-sullivan/.
Chicago: "Cillian O'Sullivan." Biography.guide. https://biography.guide/cillian-o-sullivan/.
Data last updated: 2026-09-20 · Spot an error? Report a correction.
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