Spent seven years in foster care, during which he lived in thirteen different homes.

Is an amateur boxer.

Has appeared in three films with Colin Farrell: The Killing of a Sacred Deer (2017), The Batman (2022) and The Banshees of Inisherin (2022).

Became a father for the first time at 29 when his partner Alyson Sandro gave birth to a boy named Brando, born on August 5, 2022.

Born and raised in Dublin, Ireland.

He is the fifth Oscar nominated actor to play Batman's arch nemesis, the Joker.

Prior to playing his arch enemy the Joker, he had once expressed an interest in playing Batman's sidekick Robin alongside Ben Affleck's portrayal.

Was supposed to play Yorick Brown, the lead role in Y: The Last Man (2021), but he left the project when it was still in pre-production.

He is the second non-American actor to play the DC Comics super villain, the Joker, after Heath Ledger.

As of 2024, he has appeared in two films that were nominated for the Best Picture Oscar: Dunkirk (2017) and The Banshees of Inisherin (2022).

Barry is a Manchester United supporter and featured in an advertisement video for the club and its sportswear manufacturer.