Zacatecas, Zacatecas
Tello was born in Zacatecas, Zacatecas on 1 November 1898. There, he completed his basic studies at the Christian Brothers School and at the "Instituto Científico". He moved to Mexico City to enroll at the National Preparatory School and took some courses leading to a bachelor's degree in law at both and the National Autonomous University of Mexico (UNAM) without getting a degree.