Harris says she sought a career in law enforcement because she wanted to be "at the table where decisions are made." In 1993, she started dating California Speaker of the Assembly Willie Brown, who introduced her to many powerful individuals in the California and Sacramento political and campaign management establishment. Shortly thereafter, Harris demoted veteran career prosecutor Paul Cummins, chief assistant to her predecessor, from the 80-prosecutor felony prosecution unit to Harris's former position in the DA's office.
In 2000, San Francisco's elected City Attorney, Louise Renne, recruited Harris to join her office, where she was chief of the Community and Neighborhood Division, which oversees civil code enforcement matters. Recognized by The Los Angeles Daily Journal as one of the top 100 lawyers in California, Harris served on the board of the California District Attorney's Association and was vice president of the National District Attorneys Association.