If the court ordered that he can claim the exemption every year without any conditions, it would not be advisable to claim your child in violation of the court order. Although the IRS might allow it, there would be a strong possibility of getting in trouble with the court.
For the noncustodial parent to claim the exemption with the IRS, the following must apply:
You must have signed and provided him with form 8332 or a similar statement that must be attached to his return. (It is possible that you signed this form or a qualifying statement during court proceedings)
The statement must state both parents names and social security numbers, the child’s name and the years that the dependency exemption is released to the noncustodial parent.
Although the noncustodial parent has the right to claim your son every year, the IRS has reserved several tax benefits for the custodial parent regardless of who claims the dependency exemption. In the situation where the dependent is claimed by a noncustodial parent, the child related tax benefits are divided as follows:
The noncustodial parent has to attach a signed release from the custodial parent that releases the exemption (usually on IRS form 8332).
The custodial parent can claim the follow every year that the child resides with them the majority of the year.
