There are many things that would help the situation, but your question makes me wonder if you should just hire a trainer to help you, for your own safety.
Some things I would try would be:
--take a crop with you to defend yourself
--use a rope halter and if he attempts to bite, play, etc. while you are leading him, give a sharp jerk downward on the lead rope, which will have more effect with a rope halter than a flat woven nylon one
--put him in a round pen and free-longe him, work him at a fast trot/canter...if he only bucks and kicks the air, fine, keep him moving....if he comes at you, get really aggressive right back in his face--DON'T GIVE GROUND!!!--wave your arms at him and smack him hard with the longe whip...he has learned that he scares you, and is having a great time showing his aggression....reverse that situation any time he acts up.
You said you've tried discipline, but there's a lot to knowing when and how to act with a horse like this. Timing is EVERYTHING, and that's why I think you may need help. You have to smack him immediately as his bad action is still happening. If you wait two seconds later, it doesn't have the same effect. Also, you may be "afraid" of hurting him...a lot of people today won't smack their horse or use a whip at all. A whip is simply an extension of your arm, and unless you are extremely strong, a good hard smack with it will just give the horse a sting, which is exactly what he needs--it won't injure him at all.
He needs to re-evaluate who you are. Right now he has you figured as his toy and personal slave....not a good viewpoint. You may be afraid that he won't like you if you smack him or jerk his lead rope when he is misbehaving. Actually the opposite is true. If you get his attention and make him obey you, he will show a lot more respect and attention and affection to you. You've got to get control of him, and ANYTIME he acts up, put some consequences on him that he really doesn't like. That's the only way to stop this type of behavior.
Again, for your own safety, hire a GOOD trainer....ask a lot of questions, get some help on how to handle this colt before you get hurt.