Set up a meeting with his teacher, school counselor and principal to establish a specific plan for him in the classroom. It will help his teacher and your son because you can talk to them about the problems he has had in the past and what has worked.
Ask his teacher what her discipline plan for the classroom is. Set expectations for your son by talking about what behaviors are expected in the classroom. Practice them with him, even role-playing with you as the teacher. Give him an instruction the teacher would, like “Please stop coloring and bring your papers to me.” Show him how to stop what he is doing, look up at the teacher’s eyes and answer with “Yes, Mrs. Smith.” Then he can walk directly to her desk with the crayons.
Praise him for being a good listener. Discipline is really just teaching. Better results occur when the teacher is consistent.
Remember that the first few weeks of school are rough. It is difficult to get into a schedule after the freedom of summer. Enlist the help of an older sibling or neighborhood friend to talk to your son about listening to the teacher. Ask your teacher to recommend good playmates from his class. Then use these as incentives for listening. He can earn a play date with a new school friend if he comes home with a good behavior report one day this week.
Also reinforce at home the consequences given at school. Your son needs to know that his parents and teacher are working together and will communicate when unacceptable behaviors occur. Since he tried to hit the teacher at school, he may not watch his favorite after-school cartoon or some similar consequence.