She was the first Latina elected to the Superior Court in Santa Clara County. She has been assigned to hear criminal and civil cases from arraignment to trial. Currently, she presides over Dependency cases which involve abused and neglected children. Prior to becoming a judge, she served as an executive officer for the City of San Jose. She was appointed by the Mayor and City Council as the first Independent Police Auditor where she was responsible for providing public policy in the area of public safety. She earned international recognition for developing policing guidelines that improved effectiveness and accountability in law enforcement. As a trial attorney, Judge Guerrero-Daley was in private practice. Judge Guerrero-Daley also served as an Arbitrator deciding consumer vs. auto manufacturer cases. She was also certified as a mediator in conflict resolution. Judge Guerrero-Daley was the first female Special Agent for the U.S. Drug Enforcement Administration assigned to San Jose. As a Special Agent she worked on numerous undercover operations which involved the enforcement of local, state and federal laws involving the illegal sale, transportation, importation or manufacturing of dangerous drugs and narcotics.