He attended Harvard College, where he won the Robert F. Kennedy Award given each year to a member of the varsity football team.

He ran against former Governor and Oakland Mayor Jerry Brown in the 2006 race for the Democratic nomination for state Attorney General of California.

One of the most well-publicized prosecutions by Delgadillo's office was that of entertainer Paul Reubens, more commonly known as Pee Wee Herman, for possession of child pornography.

Delgadillo's office arranged a plea bargain requiring Reubens to pay a $100 fine and serve three years of probation.

[citation needed] An agreement facilitating digital billboards in Los Angeles while he was seeking campaign funds from the industry created controversy as to possible bias in agreeing to the advertising expansion.