St. Leo’s Mission was founded in 1942 by families of La Colonia, many of whom found themselves sending sons to fight in World War II. The war brought urgency for a spiritual center for the community, according to reports from the era. The church’s first home was a small barracks building moved from the Camp Callan Army base on Torrey Pines Mesa. In 1959, the eastern portion of the church property was claimed for constriction of Interstate 5, resulting in the church’s displacement. Parishioners took over a nearby concrete platform that contained the shell of a building initially planned as a community hall and held fiestas to help raise money for a new structure. The site itself was donated by Frank “Pancho” Garcia, who ran a grocery store and cantina near his home at the corner of Valley Avenue and Genevieve Street starting in the 1920s. Desi Arnaz of “I Love Lucy” fame often played music at the temporary church site while visiting his summer home in Del Mar. Actors Pat O’Brien and Bing Crosby also were visitors.
In spite of this push to rebuild a permanent church for St. Leo in the 1960s, there was some controversy over whether two Catholic churches were needed less than a quarter-mile apart in the same community. St. James had relocated to Solana Beach from what is now the current library site in Del Mar. After intense lobbying led by Cipriana Gonzales — who took the case to the Vatican — the diocese of San Diego in 1966 agreed that St. Leo’s was a cultural as well as religious center, essential to the La Colonia community, and that it should be preserved. St. Leo’s became a mission church under the pastorship of St. James and the two parishes were joined, as they remain today.
That same year, parishioners built their modest church and bell tower from the shell on the temporary platform for just $2,000. The brass bell would ring for births, baptisms, marriages, quinceañeras, sacred Masses and funerals until 2004, when the tower was found to be termite infested and had to be taken down. After another successful fund-raising effort, a new steel tower was erected in 2012.