The Ex-Military is characterised by the way it retains the conservative aspects of The Jarhead, but has let things go a little. Jake's no longer bare-headed, but at the same time no one's going to claim he's a long-haired hippy. It implies one of two things: either the wearer has just left the army and has let his hair grow for the first time in a while, or he's been out of the army for years but still clings on to the regimented way of life, his hair being a testament to that. In neither case would the man be caught dead having hair that would flop any further than half a centimetre onto his forehead. This lid tells you that this man may have seen some things and deserves respect for it, and much like The Jarhead it would be wise not to piss him off. And there you have it - Jake Gyllenhaal and his many hairdos. With all the above in mind, I can't help but feel it would save us all a lot of time if he just went back to the haircut from Prisoners and just kept that for the rest of his films.
