Barrales was first registered as a Democrat before he ran for San Mateo County Supervisor. In 1992, he was elected San Mateo County Supervisor, and became the first elected Latino Supervisor in the county. He was re-elected in 1996. As a county Supervisor, he helped lower crime in East Palo Alto by collaborating with Sheriff Don Horsley and other cities to form the Gang Suppression Task Force. This was needed in East Palo Alto, a city that the Federal Bureau of Investigation considered the homicide capital of the United States in 1992, after 42 killings took place that year. He also supported the citizens of Redwood City in bringing the Shot Spotter to Redwood City to reduce random gun fire. Redwood City was instrumental in the development of the Gunshot Location System, which was possible through funding by San Mateo County and the major portion by the City of Redwood City. In 1998, Barrales was the Republican candidate for California State Controller, though he failed to unseat Kathleen Connell. He received 2,652,115 votes to Connell's 4,874,097 votes. Although he lost, the run for California State Controller gained him national attention. In 2001, he was appointed as Deputy Assistant to the President and Director of Intergovermental Affairs in the White House by President George W. Bush.
Private sector
After one and a half terms on the county board of supervisors he moved to the private sector, becoming President and CEO of Joint Venture: Silicon Valley Network in San Jose, California. Following his stint in the White House he became President and CEO of the San Diego Regional Chamber of Commerce in December 2006.
Notation
Barrales is listed among the 100 most influential Hispanics/Latinos in the United States.
Barrales served as a member of the Speaker's Commission on the California Initiative Process.
Barrales served as Vice-Chairman of the California Commission on Local Governance for the 21st Century.
Barrales served as a member of the California Speaker's Commission on State and Local Government Finance.
Barrales was recently featured in San Diego Magazine for his contributions to the strength of the Latino community in San Diego.
Community service
He was a founding member of Garfield Charter School, in the Redwood City Elementary School District. Garfield Charter School was one of the first charter schools in California. He was instrumental in getting Garfield's Charter and secured funding for the first years. He also served as Director of the Peninsula Conflict Resolution Center.