Yes, you DO need to apply for an ITIN for the child when you file jointly with your wife, claiming the child as a dependent and qualifying for the $1,000 Child Tax Credit. You MAY need to wait until you qualify for the Substantial Presence Test; that depends on WHEN you first arrived in the U.S.
To apply for an ITIN, you need to complete Form W-7 for your child. You need to make a photocopy of his/her passport, then get photocopy notarized. This can be done at your local bank in most states in the U.S.
If you need professional help to submit the Form W-7 and tax return, email me at
[email protected].