This is about the age that chicks start working our their pecking orders. He is challenging your place in it so is trying to dominate you.
What I do when they are this age is as soon as he jumps me I thump him up side his head with my finger (not so hard as to injure him) then chase him around the brooder box for a while. Just don't do it so vigorously that you cause the others to panic to the point they could injure themselves. You just want to keep him moving away from you. Chase him around a bit and every time he stops your thump his head again until he avoids you every time you put your hands in the box. This should convince him that he is NOT above you in the pecking order.
When they are old enough to go onto the ground don't ever move out of HIS way. Make him move out of YOUR way. Every time. This will keep him reminded that you are the boss bird and not him.
There are the occasional cock birds that simply will not be convinced so are better off in the pot, but most of them if you start in the brooder and don't let up on them will be well behaved.
.....Alan.