7. Stop-Loss (2008)
Unquestionably one of the actor's darkest roles to date - if not quite as grim as what takes our #1 spot -
Stop-Loss sees Gordon-Levitt playing PFC Tommy Burgess, a soldier returning from duty who finds himself encountering marital issues, likely as a result of the toll that war has taken on him. Gordon-Levitt harnesses a frightening level of intensity here as the angry, but ultimately forlorn young man unable to cope with the damaging effects of war, and the subsequent effect it has on his marriage, such that he eventually commits suicide. Demonstrating the actor's ability to imbue a film with both heart and soul, his character's demise makes way for a pivotal showdown in the film between Ryan Phillipe and Channing Tatum's soldier characters, though it's fair to say that he in fact outdoes both of their performances by a fair way. What could have been a relatively standard war critique is elevated significantly because of his involvement.