He married Ma. Matilde TRUJILLO, daughter of Jose Benito TRUJILLO and Ma. Rafaela CORDOVA.
- Juan Florencio Romero, b. 1921
- Rosita Odilia "Rosa" (twin) Romero, b. 1925
- Ruben (twin) Romero, b. 1925
- Priscilla Romero, b. 1930
- Candido Romero, b.
- Ma. Lucilla/Lucille Romero, b. 1934
- Leo Romero, b. 1936
At the age of 55, Guillermo died on 17 June 1949 in Bernalillo County, New Mexico. He was buried in Llano, NM.
- 1910 U.S. Census: New Mexico Territory/Taos County
- 1920 U.S. Census: New Mexico/Taos County
- 1930 U.S. Census: New Mexico/Taos County