Not much is known about this actor except that he just wrapped production on The Cold Light of Day and stars in the upcoming Tarsem Singh film Immortals, in which he plays the Greek warrior Theseus.
Here is what Snyder had to say about directing the movie and the casting of Henry as Superman:
In the pantheon of superheroes, Superman is the most recognized and revered character of all time, and I am honored to be a part of his return to the big screen. I also join Warner Bros., Legendary and the producers in saying how excited we are about the casting of Henry. He is the perfect choice to don the cape and S shield.I think choosing a relatively unknown actor to play Superman is a great idea. Now all they need to do is choose a script.
Targeted for release in December 2012, the new Superman movie will be distributed worldwide by Warner Bros. Pictures, a Warner Bros. Entertainment Company.