From how I am interpreting your post, it appears that you had the dependent child the most nights of the year. That makes you the custodial parent.
IRS, not local court decisions, apply to the situation when it comes to federal taxes.
You basically have two classifications for separated or divorced parents.
Custodial Parent - This is the parent with whom the child lived for more than 182 nights (not days) of the tax year. The nights do not have to be consecutive. Temporary absences, such as summer camp, school, hospital stays, etc count for this, provided the child returns to the home of the custodial parent at the end of the temporary absence. (There are exceptions for the "return" part). If the parents lived together for part of the tax year, then the custodial parent is the parent with whom the child lived the most nights of the tax year. The custodial parent has the right to claim the child as their dependent on their tax return.
Non-Custodial Parent - This is the parent that does not qualify as the custodial parent, using the guidance for custodial parent above. the non-custodial parent can claim the child, only if the custodial parent provides the non-custodial parent with a signed IRS Form 8332 releasing their right to claim the child, to the custodial parent. While the non-custodial parent can claim the child if they have a signed Form 3332 from the custodial parent, the custodial parent still retains the right to claim the EIC for that child, if the child qualifies them for that EIC.
