After incumbent state assemblyman Charles Calderon decided to seek a seat in the California Senate, Becerra launched a grassroots campaign for the California State Assembly, defeating Calderon's Senate aide Marta Maestas in the Democratic primary. He went on to defeat Republican Lee Lieberg and Libertarian Steven Pencall, receiving 60% of the vote. Becerra served one term in the State Assembly, representing California's 59th district, from 1990 to 1992. As a state legislator, Becerra worked to pass a law that would increase gang members' sentences.