Child Support and Good Moral Character
Good Moral Character basically means that you've been a law-abiding resident who adheres to the basic moral standards of the U.S. community. The U.S. Citizenship and Immigration Services (USCIS) typically looks at your conduct during the five years immediately before you file your application (or three years if you're married to a U.S. citizen).
Having unpaid child support can impact your good moral character requirement negatively. You will need to make arrangements to pay off the child support you owe, and present evidence that you are on a path to being up to date with your child support payments.