I like very much what you have done here, but his background is distracting. If you have an opportunity to shoot him again, my suggestions would be as follows:
Move around to try to get more of him and less of anything else in the frame. Maybe even crop off some of him in the frame to just head and shoulders.
I think your camera gives you the ability to change the aperture a bit, if so, shoot with a wider aperture. try a few shots with the smallest number you can get to and then slowly make it larger: f2.8, f4, f8, etc...
You nailed it with sharpness and color, I wouldn't change those at all!
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{K:4294} 11/6/2004