maybe try leaning him forward at the waist so the light doesn't catch all those medals (and metal on his hat)? That bright spot really draws my eye away from his face.
I always wonder if these guys have just seen too much to smile? Be sure to thank him for his service on my behalf.
How can someone not appreciate a photo like this. Nice job. The background vignetting is not very smooth however. Was that an effect of the capture, or the processing? Either way, something I would recommend to look in to next time.