Kearney was born in London to Irish parents before relocating to Dublin aged five. She studied Drama and Classics at Trinity College, Dublin, graduating with honours, before training at the Bristol Old Vic Theatre School, graduating in 2009. Her career began in theatre, with performances in productions such as Man of Mode alongside Antonia Thomas and Theo James, On the Razzle, Three Sisters, Oh! What a lovely War! and Othello.
She stars as the female lead London in the Netflix original comedy series Flaked alongside Will Arnett. Kearne portrays an attractive newcomer to Venice who gets caught in a love triangle with the characters portrayed by Will Arnett and David Sullivan. The role is Kearney's first major comedy television series. The series premièred on March 11, 2016 with all eight episodes released simultaneously.
It was confirmed in July 2016 that Flaked will be returning for a second season in 2017 
|2010||Primeval||Jessica 'Jess' Parker||Webisodes|
|2011||Primeval||Jessica 'Jess' Parker||TV series (13 episodes: 2011-2012)|
|Holby City||Jenny Proctor||TV series (2 episodes)|
|Fast Freddie, The Widow and Me||Stacey||TV Movie|
|2013||Jet Stream||Angel||TV Movie|
|2014||Tyrant||Katharina||TV series (2 episodes: 2014)|
|2015||The Following||Daisy||TV series (Recurring S3 - 11 episodes)|
|2016||Flaked||London||TV series (Regular - 8 episodes)|
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- "Ruth Kearney teases 'Primeval' role". Digital Spy.
- "ITV confirms new 'Primeval' cast". Digital Spy.
- "Shows". STV Shows.
- "Irish actress Ruth loves LA and her Netflix leading role". Independent.
- "The Following: Will Ryan finally pay for his sins?". Entertainment weekly.
- https://deadline.com/2015/08/will-arnett-flaked-ruth-kearney-cast-lead-netflix-series-1201505814/ Deadline: Ruth Kearney Cast As Female Lead
- http://www.irishtimes.com/business/media-and-marketing/netflix-releases-first-snippet-of-dry-comedy-flaked-1.2539876 Netflix releases first snippet of ‘dry comedy’ ‘Flaked’
- http://www.slashfilm.com/flaked-trailer/ ‘Flaked’ Trailer: Netflix Really Loves Will Arnett
- Jennifer Lee (February 18, 2016). "Meet the newcomer of Netflix's soon-to-be-released new comedy, 'Flaked'". Filler Magazine.
- Lisa de Moraes (January 17, 2016). "Netflix Unveils Premiere Dates For 'Orange Is The New Black,' 'The Get Down,' 'Flaked' And Others". Deadline.com.
- http://www.hollywoodreporter.com/live-feed/official-netflix-renews-flaked-season-915320 Netflix renews Flaked
- Maido, Jenille Cristy (11 April 2014). "Shailene Woodley and Theo James Dating; Real or For 'Reel?'". International Business Times. Retrieved 17 July 2014.
- "Theo James: Bad breath turns me off". Belfast Telegraph. 10 April 2015. Retrieved 29 May 2015.