Verify you can file for custody in Illinois. You can file in Illinois if it is the home state of the child, in most circumstances. The Uniform Child Custody Jurisdiction and Enforcement Act, which applies in Illinois, dictates which state you can file in.
Determine which county in Illinois to file in. If you are filing for custody as part of a divorce, jurisdiction is determined by where you file for divorce. If you are filing under other circumstances, usually you have to file in the county where the child lives. Consult Illinois Combined Statutes Section 750, Part VI Custody, for detailed information on jurisdiction.
Draft a petition for custody or include a request for custody if you are filing as part of another action. A parent can request custody in Illinois in a petition for custody; petition for dissolution of a marriage; petition for dissolution of a civil union, if the child was adopted; paternity petition; or a petition for protection.
Include in your petition information about the factors that govern child custody decisions, as detailed in the Illinois statutes. For example, the court will consider the parents' wishes; child's wishes; child's adjustment to her present home and relationship with both parents; one parent's attitude toward cooperating with the other parent; health of all parties; instances of abuse or violence; and whether any party is a sex offender.
Obtain and complete a UCCJEA affidavit. State all the places where the child has lived, who else lived there, the primary caretaker in each location and any court cases that involved the child. You can find a sample form by conducting an Internet search or requesting it from an online legal document provider.
Fill out a summons and cover sheet, both of which you can obtain from the clerk of court in the county where you are filing. The summons must provide information to the other party about where he should respond to your petition.
Make sure your petition is properly verified, which means you sign it in the presence of a notary public or an attorney signs the forms for you.
File your cover sheet, summons, petition and UCCJEA affidavit with the clerk of court and pay the required filing fee. Obtain a file-stamped copy of the documents to serve on the other party, as well as a document called an affidavit of service.
Serve the documents on the other parent by hiring a sheriff's deputy or private process server. The deputy or private process server will fill out the affidavit of service at the bottom of the summons and return it to you.
File the summons with the signed affidavit of service with the clerk of court. Keep a copy so you will have a record of when the other party was served.
Request a hearing and wait for the other party to respond within the 30 days allowed.