Although Malachy and Aran spent their early childhood years in London, their parents eventually moved them back to a wifi-free home in Dublin, Ireland in 2014. "We wanted them to be Irish, I suppose," Cillian Murphy told The Guardian a few years later, adding, "It's amazing how quickly their accents have adapted. Even within a year of moving back, they are fading into this rakish west Brit kind of thing. Which I think, hopefully, will get them lots of girls when they're 15."

Cillian Murphy is constantly impressed by his sons' confidence. That being said, Malachy still feels a bit frightened when watching his dad in certain films . . . especially if they involve zombies. "I was pretty proud of how well ["28 Days Later"] stood up," Cillian Murphy told Esquire in 2022, explaining that he showed the early 2000s disaster flick to his oldest son."[Malachy] loved it. He was really scared," said the actor. 

However, there's one Cillian Murphy character that Aran, Malachy, and Yvonne McGuinness got to know more than others: the Irish gang leader Thomas Shelby from the long-running series "Peaky Blinders." Murphy's family might even describe him as "not being all there" while the show is in progress, per Esquire Middle East. After becoming Shelby, returning to himself (and his family) takes time. "My wife can see it happening," the actor explained to The Guardian. She'd say, "'OK. Tommy's gradually leaving. I'm getting Cillian back.'"