Sig Sanchez was born on November 11, 1920 in Hollister California. Sanchez was the second eldest of eleven children. The Sanchez family moved to the San Felipe area of south Santa Clara County in 1928, picking prunes for family income. A man with strong business skills, Sanchez eventually purchased his own farm in Gilroy and engaged in ranching.

In 1953, Sanchez was elected to the Gilroy City Council. Four years later, he was elected to the first of his two terms as Mayor. In 1963, a reporter encouraged Sanchez to run for supervisor and he consented, thinking he could serve his constituents better at the county level.

When Sanchez took office, the boundaries of the county's supervisorial districts were so disproportionate that Sanchez had only 12 percent-25,000 people-of the county population in his south county district. By the end of his first term, however, the District 1 supervisor represented 150,000 people.

Sanchez believed that the residents of the south county should become more involved in county government, particularly as development issues came to the forefront. He was concerned that farm owners in the south county did not reap the same financial rewards from development that north county landowners had obtained before controls were put into place.

After 16 years in office, Sanchez left the Board of Supervisors in 1978. Two years later, he was appointed to Santa Clara Valley Water District, where he would serve for 29 years.

Sanchez was respected by local reporters, often affectionately referred to as "El Presidente" or "El Patron." Well-known as a cigar smoker, Sanchez was forced to alter his habit when a no smoking rule was enacted for board chambers, thenceforth merely chewing on the cigar during board functions. Sanchez has a 10-mile portion of state Highway 101 named for him in honor of his 12-year effort to lobby government agencies to build it.