1. On jest najbardziej znany z ukazywania Petyr “Mały palec” Baelish w serii gier o Tron HBO, Tommy Carcetti in the HBO series The Wire, CIA operative Bill Wilson in The Dark Knight Rises, Stuart Alan Jones in the Channel 4 series Queer as Folk, and John Boy in the RTÉ Television series Love/Hate.
2. Gillen played Stuart Alan Jones in the groundbreaking Channel 4 television series Queer as Folk and its sequel, for which he received a British Academy Television Award nomination for Best Actor.
3. W 2004, having been spotted by producers in The Caretaker, Gillen was cast as Tommy Carcetti in the acclaimed HBO series The Wire, for which he received an Irish Film & Television Award for Best Actor in a Lead Role in Television.
4. W 2008, he was named an “Irish cult hero” by the Sunday Tribune.
5. Pojawił się w 2009 filmu 12 Policzone, and in July of that year, he appeared in the one-off BBC2 drama Freefall.
6. W 2011, Gillen began playing Petyr “Mały palec” Baelish on the HBO series Game of Thrones, for which he received his second Irish Film & Television Award nomination. He starred as cop killer Barry Weiss in the British crime-thriller Blitz and in the British horror film Wake Wood.
7. He played crime boss John Boy in the acclaimed Irish crime-drama Love/Hate, for which he received his third Irish Film & Television Award nomination and second win.
8. Gillen also starred as Janson in the second film, The Scorch Trials, in the Maze Runner trilogy.