In this new job, Warren tried criminal cases, defended civil and criminal suits against county officials, advised county boards of education about civil liability issues, and wrote legal opinions on various issues – such as real estate matters – for the county board of supervisors. Along the way, though, he discovered that his real first love was law enforcement and public service. Within three years, Warren had become the Alameda County’s District Attorney’s chief deputy. The county DA was Ezra Decoto, but in 1925 Decoto resigned and Earl Warren was chosen by the county’s Board of Supervisors to fill the unexpired term left by Decoto’s resignation. The next year, at the end of the term, Warren ran for the position and became Alameda County’s
