He attended Riverside City College in the 1920s along with classmate John Gabbert, who ultimately became a Superior Court Judge. Following his time at Riverside Community College, he attended Whittier College and then the University of Nevada.
He had many careers and avocations throughout his life, including farmer, cattle rancher, surveyor, and mineralogist. He also served as an engineer for the California Division of Highways for nearly 20 years. Soil conservation Costo was key in the establishment of the Anza Soil Conservation District, now known as the Elsinore-Murrieta-Anza Resource Conservation District.
Native American advocacy He also served as a lobbyist fighting for Native American land rights for two years in Washington, District of Columbia He founded the American Indian Historical Society in 1950 in an effort to ensure scholarly examination of Native American lives as opposed to the stereotypes so prevalent in United States" society at the time.
The Costos founded the Indian Historian Press, a for-profit publishing house dedicated to publishing titles documenting or related to the Native American experience in the United States. University of California, Riverside advocacy Death and afterward Rupert Costo died on October 20, 1989 at his home in San Francisco, California.
Legacy His extensive personal library documenting the Native American experience in the United States was donated to the University of California Riverside Libraries in May 1986. The Costo Chair in American Indian History at the University of California, Riverside was named in his honor.
Costo and his wife Jeannette opposed the efforts within the Catholic Church to name Father Junipero Serra a saint based on the claim that he treated Native Americans in an inhumane fashion.
Costo served as a member of the governing board of Cahuilla Reservation for more than 20 years and its spokesman for 8 years. And was a member of the American Indian Federation in the late 1930s.