Eastin began her political career in 1980 as a Member of the Union City Council. As a council member she represented the city on a variety of boards including as a Member of the Alameda County Library Commission, which she chaired for 5 of the 6 years she served on it. She also represented the city on the Solid Waste Management Authority, where she successfully advocated for a Recycling Subcommittee. She chaired the SWMA and she represented Union City on the Association of Bay Area Governments.