---
name: "Cillian Sullivan"
canonical: "https://film.one/person/cillian-sullivan"
fi1m_id: "cillian-sullivan"
tmdb_id: 3337044
roles: ["Actor"]
reviewed_on_fi1m: 1
average_as: "actor"
average_over: 1
updated: "2026-09-24T03:41:56.704215+00:00"
licence: "© Fi1m Ltd. Written by AI under a human editor; checked against sources before publication. Quote with attribution and a link to the canonical URL."
---

# Cillian Sullivan

## Identity

Cillian Sullivan

- **Canonical:** https://film.one/person/cillian-sullivan
- **Type:** Person
- **Fi1m ID:** cillian-sullivan
- **TMDB ID:** 3337044
- **Same entity:** https://www.themoviedb.org/person/3337044

Actor.

## Details

- **Work:** Actor
- **Elsewhere:** https://www.themoviedb.org/person/3337044

## Streaming the US now

- **Netflix:** [*Blue Moon*](https://film.one/film/blue-moon.md) (78)

For United States; add `?region=XX` for another country.

## Biography

Cillian Sullivan is an actor. He played Stephen Sondheim, credited as Stevie Sondheim, in the 2025 film *Blue Moon*. He has also appeared in the 2024 film *Spilt Milk* as Bobby O'Brien and in several short films, including *Blue* (2020) as Mark and *A Song* (2025) as Young Boy.

*Sources: imdb.com, en.wikipedia.org.*

## On Fi1m (1)

- *Blue Moon* (2025), Fi1m 78, as Stephen Sondheim — [page](https://film.one/film/blue-moon.md)

## Complete filmography (6)

Every credit, newest first. Titles without a page can be requested for review on the HTML page.

- *Kova’s Courage* (2026), as Siku
- *Blue Moon* (2025), as Stephen Sondheim — Fi1m 78, [page](https://film.one/film/blue-moon.md)
- *A Song* (2025), as Young Boy
- *The Things We Do* (2025), as Cillian
- *Spilt Milk* (2024), as Bobby O'Brien
- *Blue* (2020), as Mark

---
© Fi1m Ltd. Written by AI under a human editor; checked against sources before publication. Quote with attribution and a link to the canonical URL. Canonical: https://film.one/person/cillian-sullivan