How does Holden describe himself physically?
This question would be easy to answer if Holden Caulfield could maintain a consistent thought process. But he's all over the place, so to find a full description of his physical appearance means wading through large swaths of the book.
Chapter one probably contains the most information in a single location. Holden tells his readers that he is six foot two and a half inches tall. He also tells readers that he has gray hair. He specifically says that the gray hair is on the right side. I'm assuming it's on both sides, but perhaps just more of it on the right side.
The one side of my head--the right side-- is full of millions of gray hairs.
Later in the book Holden tells his readers that he looks a lot older than he really is. Apparently it must be true, because he doesn't struggle to obtain alcohol. I believe that his older appearance is due in part to the fact that Holden says that he is a heavy smoker. Smoking causes people to age more quickly.
In addition to being tall, Holden is skinny. He comments several times on the fact that he is thin.
I'm a very light eater. I really am. That's why I'm so damn skinny. I was supposed to be on this diet where you eat a lot of starches and crap, to gain weight and all, but I didn't ever do it.
One other specific detail about Holden's physical appearance is that he wears a red hunting hat.