Ahern was born to parents Mary and Maurice grew up in Rathfarnham with his two brothers.[3] He attended St Mary's Boys National School (BNS) and then Coláiste Éanna. He went on to graduate with a double Bachelor of Law and Business (BBL) from University College Dublin in 2007 and a Master of Science (MSc) in Criminal Justice Policy, Human Rights, Criminology, and Corporate Crime from the London School of Economics (LSE) in 2009.[4]