In 1981, he earned a Masters of Law degree with emphasis in Labor Law from the George Washington University National Law Center. Later that year Larry returned to Seattle to run Randy Revelle's campaign for King County Executive. Revelle won the election, and Larry served as his Chief of Staff until 1986. He learned about every aspect of King County government as he advised the Executive on all major policy, programmatic, and political decisions. After Revelle left office, Larry served as Executive Director of a 55-member Seattle law firm, Shidler McBroom Gates & Lucas.

Larry's interest in public service never waned, and in 1988 he ran and won election to the Washington State House of Representatives. He went to Olympia to represent the 36th Legislative District, where he served for two terms as a member of the House Education, Local Government, Environmental Affairs, and Revenue Committees. He was an author and prime sponsor of the 1990 Growth Management Act, as well as legislation to prevent oil spills in Puget Sound. He also fought successfully for smaller class sizes in public schools and adequate funding for K-12 education.