Ursulo was the son of Liborio Montoya and Cleofes Barela. Identified siblings were: Celestino and Pedro. Identified half-siblings were: Maria Aurora, Susana, Maria Celia, Manuel Baldemar, Maria Josefita "Josie", Florila "Flora", and Jose Adonais Rudolfo. On 16 Jan 1924, Ursulo married Lucia Martinez. Their identified children were: Elisardo, Jose Asencio "Ernie", Marvin, Robert, Marlene, and Sherlene.