He was the first of two children born to his mother, Maria del Carmen (a hairdresser) and to his father, Jose Luis Casillas (a teacher).
ລາວເປັນເດັກນ້ອຍຄົນທໍາອິດທີ່ເກີດມາຈາກແມ່ຂອງລາວ, Maria del Carmen (ຜູ້ເຮັດຜົມ) ແລະກັບລາວ, Jose Luis Casillas (ຄູສອນ).