Born in Medina de Rioseco, Valladolid Province, Amigo Vallejo studied medicine in Valladolid before joining the Franciscan order, later studying philosophy in Rome and psychology in Madrid.
Lahir di Medina de Rioseco, Provinsi Valladolid, Amigo Vallejo belajar kedokteran di Valladolid sebelum bergabung dengan ordo Fransiskan, kemudian belajar filsafat di Roma dan psikologi di Madrid.