O'Shaughnessy was born in Galway, County Galway. Her family moved to Reading, Berkshire when she was 9. She studied ballet, tap, modern and jazz dance, throughout her school years in Reading, UK. She returned to Galway a decade later where she pursued a career in theatre.
O'Shaughnessy's most notable stage role to date is that of Salome, for the Gate Theatre in Dublin. Other stage work has included The Shaughraun for the Abbey Theatre in Dublin, which transferred to the West End's Albery Theatre in 2005. In 2006 she appeared in the UK premiere of Blackwater Angel by Jim Nolan at the Finborough Theatre, London. Other work for the Gate Theatre includes Arms and the Man, Oliver, The Importance of Being Earnest, Pride and Prejudice, Blythe Spirit, Present Laughter (which toured in Charleston, South Carolina), See You Next Tuesday, and Cat on a Hot Tin Roof. She played Cate in the Irish debut of Sarah Kane's play Blasted.
Film and television
Her film roles include Clara in Goldfish Memory, The Halo Effect, and The Stronger. Other theatre work includes playing Hilde Wangle in Lady from the Sea and Petra Stockman in Enemy of the People at the Arcola Theatre, London, and Amy in 'The Night Alive', by Conor Mc Pherson, at The Geffen Playhouse, in Los Angeles, directed by Randall Arney. She stars as Jessica Hyde in the television series Utopia. In 2015, she starred with David Troughton in the comedy romantic horror film Nina Forever, written and directed by the British duo, the Blaine Brothers.
|1999||Warlock III: The End of Innocence||Kris' Friend|
|2000||Clubbing||Femme Fatale||Short film|
|2001||Freaky Deaky 10 to 1||Unknown||Short film|
|2004||The Halo Effect||Suzie|
|2005||Still Life||Woman||Short film|
|2005||Malice Aforethought||Florence||Television film|
|2006||The Secret Language||Máthair|
|2009||Malice in Wonderland||Hooker|
|2015||Nina Forever||Nina||Pending – Fangoria Chainsaw Award for Best Supporting Actress|
|2007||Trouble in Paradise||Síofra McShane|
|2012||Vexed||Sarah Stockwood||Series:2 Episode:5|
|2013||Agatha Christie's Poirot||Katrina||Episode: "The Labours of Hercules"|
|2017||The Living and The Dead||Martha Enderby||2 episodes.|
- Gerard Gilbert (July 26, 2014). "Utopia star Fiona O'Shaughnessy: 'I don't like to watch too much". The Independent. Retrieved February 13, 2016.
- "SXSW 2015: First Teaser Trailer for Nina Forever". Dread Central. Retrieved February 13, 2016.
- "Never mind Oscar, here's the 2017 FANGORIA Chainsaw Awards Nominees Ballot!". FANGORIA®. Retrieved February 14, 2017.