The Australian actor will play Jack, the son of Bruce Willis's John McClane in forthcoming sequel A Good Day To Die Hard.
Courtney reportedly beat out The Hunger Games star Liam Hemsworth to win the role, which was also coveted by the likes of Paul Walker, Milo Ventimiglia and Breaking Bad's Aaron Paul.
The character is described by 20th Century Fox as "an apple that has not fallen far from the tree" and "may even be more of a hardass than his father".
A release continues: "Despite their differences, they must work together to keep each other alive - and the world safe for democracy."
A Good Day To Die Hard, directed by John Moore, is set for release on February 14, 2013.
Watch a trailer for Die Hard 4.0 below: