Jack Gleeson (born 20 May 1992) is an Irish actor who has worked in television and film. He has a minor role in the film Batman Begins and received a number of outstanding reviews for his lead role in the film All Good Children, with Variety describing him as "the pic's big discovery."
He starred in HBO's Game of Thrones as Joffrey Baratheon. He was announced in the role on 19 July 2009. He was part of the starring cast from Season 1 until Season 4 when he was killed off. In 2012, he announced his intention to retire from acting to focus on his studies once his work on the show was complete.
Gleeson admitted he was not entirely aware of the hatred of Joffrey before he was given the role. He said he had read some synopses but didn't know that Joffrey was quite the monster he appears to be in the show. Gleeson 'subconsciously' based his portrayal of Joffrey on Joaquin Pheonix's performance as the emperor in the 2000 film Gladiator. 
Gleeson was born in Cork, Ireland. He is a student of Trinity College Dublin and a member of DU Players. As a result, Gleeson's natural speaking voice actually has a pronounced Irish accent: the upper-class, Received Pronunciation accent he adopts while playing Joffrey on-screen is a conscious part of his performance. In the Blu-ray commentary for "Lord Snow", Sophie Turner (Sansa Stark) explains that for amusement between takes, the English-accented Turner and Irish-accented Gleeson would imitate one another's accents.
Gleeson said that when he was cast he read ahead on Wikipedia, so he already knew how his character ultimately died, instead of it coming as a shock in Season 4.
|Season One credits|
|Winter Is Coming||The Kingsroad||Lord Snow||Cripples, Bastards, and Broken Things||The Wolf and the Lion|
|A Golden Crown||You Win or You Die||The Pointy End||Baelor||Fire and Blood|
|Season Two credits|
|The North Remembers||The Night Lands||What Is Dead May Never Die||Garden of Bones||The Ghost of Harrenhal|
|The Old Gods and the New||A Man Without Honor||The Prince of Winterfell||Blackwater||Valar Morghulis|
|Season Three credits|
|Valar Dohaeris||Dark Wings, Dark Words||Walk of Punishment||And Now His Watch Is Ended||Kissed by Fire|
|The Climb||The Bear and the Maiden Fair||Second Sons||The Rains of Castamere||Mhysa|
|Season Four credits|
|Two Swords||The Lion and the Rose||Breaker of Chains||Oathkeeper||First of His Name|
|The Laws of Gods and Men||Mockingbird||The Mountain and the Viper||The Watchers on the Wall||The Children|