Sullivan dropped out of her graduate program at the University of Washington in 1983 to run for county council against Republican Scott Blair.
[1] Early in her career, King County experienced significant population growth, and the council passed a comprehensive redevelopment plan.
"[2] Sullivan and councilmember Greg Nickels endorsed and advocated for a 1988 advisory vote on developing a rail transit system, which voters overwhelmingly approved.
[1][4] She fought against citizen initiatives by anti-tax advocate Tim Eyman that would reduce the county's income from property taxes and vehicle license fees.
[4] Ferguson critiqued Sullivan on her reliance on donations from developers, supporting Sound Transit, and her reluctance to shrink the council from 13 seats to 9.