I have a 15 year old son that acted very similar to yours in his younger grades! Good news: He is a very kind-hearted, sweet, caring kid who has lots of friends. Bad news: He doesn't really think before he acts, and cares nothing about grades , but pulls it out each report card to avoid being grounded! But here is what I have learned about how to deal with him. First, he is a boy. School is not really designed for boys (unless you get a teacher who has a boy herself!). They are required to sit in one confined space, listen and write...boring! With that, you need to work something out with the teacher.
My son would have to change his color about 5 minutes after he got to school. So for him, he was already in trouble, why not live it up for the rest of the day? When I explained to the teacher that she had lost her "battle" with him so soon, and therefore, she was totally powerless for the rest of the day, but if she was able to redirect a little, give 3 strikes before he was out, or even gave the option to re-earn his color back she would be able to get a little more co-operation. One thing I demanded was that if he had already moved his color once, and was on the brink of moving it again, he had to immediately go to the counselor's office. It gave him and the teacher a cooling off, and the counselor was able to talk him through a few techniques to get through the day.
One thing I wanted to make sure of was that any infraction he got in trouble for was one that the teacher saw herself. It became a cycle where a child would tattle on him and he would be in trouble, so if anything went wrong, well it must have been him. And I would request the teacher write specifically what happened and what was going on around him when it happened so that we could possibly identify trouble spots (however, it was amazing how much less he got in trouble, when the teacher had to put forth that extra effort too!) Stay in constant contact with his teacher, and volunteer or go eat lunch with him as often as you can.
And, I know it sounds counter-productive, but he didn't get in trouble at home unless it was a serious infraction. He had already been in trouble at school, had to sit out at recess, so no point in punishing again. Although he did know we were disappointed, and we always praised heavily when he didn't get in trouble that day. A hug and kiss, and a little "do better tomorrow" takes alot of pressure off of a little one. I also do not believe in spanking...sorry, but my husband does not hit me when I have a bad day, and I don't believe I should hit my kids when they have a bad day either..we all mess up sometimes. We have logical consequences in our house. For example, the kids are "fined" for various infractions (along the same lines as a police officer writing a ticket). My kids pay $1 for me to pick up their shoes and put them away (cleaning fee), $2 for jumping on the furniture (so I will be able to buy a new couch one day) and $5 for asking the same question just in a different form that I have already told them the answer to (no, you may not play in the street no matter how many ways you ask). They earn money buy doing extra chores. Recently with my son's grades dropping, he has been earning less lunch money to spend in the snack line..hey, uneducated people make less money, so therefore when you bring your grades up you get a raise!
There is a light at the end of the tunnel, although I know it doesn't feel that way now. One day he will be telling you why he felt he needed to lie, or that he feels that he was still wrongly punished, or really how the teacher was that year.
I wish you and your son all the best!