Establish legal guardianship of a child by filing a petition with the court, says FindLaw. The petition should state an interest in obtaining guardianship and should be accompanied by a letter of consent from the child's parents.
Once it has received a petition, the court schedules an interview with a person seeking guardianship, according to FindLaw. Interviews may also be conducted with the child, anyone who has an interest in the child, and with the child's parents, if they are available. A criminal background check on the person asking for guardianship is often conducted, and in some cases, the court orders a home inspection.
After reviewing the information presented, the court grants legal guardianship of a child if it determines that it is in the best interest of the child, says FindLaw. In most states this requires people given guardianship to sign an oath stating they accept the responsibilities involved. Once the petition is approved, the court issues an order to establish guardianship.
Guardianship is usually granted only if both of the child's parents agree unless only one is available, notes FindLaw. If parents have had their rights legally terminated or they have abandoned a child, a guardian may be appointed. If a court finds that it is in the best interest of the child to establish a guardian, the court removes a child from the parents' custody. To obtain guardianship in the face of parents' objections typically requires proving the parents are unfit.