A legal guardian is a person who has the legal authority (and the corresponding duty) to care for the personal and property interests of another person, called a ward. Guardians are typically used in three situations: guardianship for an incapacitated senior (due to old age or infirmity), guardianship for a minor, and guardianship for developmentally disabled adults. A legal guardian is a person who has the legal authority (and the corresponding duty) to care for the personal and property interests of another person, called a ward. Guardians are typically used in three situations: guardianship for an incapacitated senior (due to old age or infirmity), guardianship for a minor, and guardianship for developmentally disabled adults.