Since 1997, Guardino has been CEO of the Silicon Valley Leadership Group, a public policy trade association that represents over 350 of Silicon Valley's most respected employers. He held an executive position in governmental affairs with Hewlett-Packard and spent six years on the staff of Central Valley Assemblyman Rusty Areias. In 2007, Governor Arnold Schwarzenegger appointed him to a four-year term on the California Transportation Commission. He was reappointed twice by Governor Jerry Brown, and in 2019, Governor Gavin Newsom appointed him to his fourth consecutive four-year term.