Rod Diridon, Sr. began his political service in 1971 as the youngest person ever elected to the Saratoga City Council. Three years later in 1974, he was elected to the Santa Clara County Board of Supervisors, defeating a 14-year incumbent. Throughout his 20 years on the Santa Clara County Board of Supervisors, Rod Sr. co-chaired the early Parks Charter Measures, created the Los Gatos Creek Trail Board and was an ardent environmentalist. A most effective proponent of public transportation, Rod Sr. is considered the “father of modern transit” in Santa Clara County and credited with countless achievements including building the light rail system. The main train station in San Jose was renamed "The Diridon Station" in his honor, a fine tribute to a railroad family.
Rod Diridon, Sr. is the only person to have chaired the San Francisco Bay Area’s three regional governments: the Metropolitan Transportation Commission, the Bay Area Air Quality Management District, and the Association of Bay Area Governments. He chaired nine successful rail system development project boards. He retired from political service due to term limits in 1995 after completing six terms as chair of both the Santa Clara County Board of Supervisors and the Transit Board. Rod Diridon, Sr. currently serves as the Executive Director of the Mineta Transportation Institute.