Lynne De Bruin was first elected County Supervisor for the 16th District in 1992. In 2004, after re-districting changed district boundaries, Supervisor De Bruin was elected to represent the new 15th Supervisory District. She was re-elected to the 15th District in 2008.  Supervisor De Bruin is a member of the Judiciary, Public Safety, and General Services Committee, the Economic and Community Development Committee and the Personnel Committee.

Supervisor De Bruin serves on the Lakefront Development Advisory Commission, the Special Needs Housing Commission, the I-94 Zoo Interchange Stakeholders Committee, the Aquatic Advisory Committee, and the Golf Course Master Plan Committee. During her time in office, Supervisor De Bruin has served on 45 special county committees and 19 community groups.

Supervisor De Bruin graduated from Seaholm High School in Birmingham, Michigan and received both a Bachelors degree in Nursing and a Masters degree in Public Health from the University of Michigan - Ann Arbor.

Supervisor De Bruin currently serves on the Board of the Marcus Center for the Performing Arts, is an ex-officio member of The Park People Board of Directors and serves on the governing board of her church. She is a member of multiple neighborhood associations serving 15th District residents and is active in all district park watches.

Supervisor De Bruin was a member of the former State Health Policy Council, which wrote the state health plan. She is a member of the Mental Health Master Plan Implementation Committee and a former Milwaukee Elections Commissioner. Previously, Supervisor De Bruin served as the Health Education Coordinator for the Sixteenth Street Community Health Center and is the past president of Cooperation West Side Association, a community organization working for neighborhood safety. Supervisor De Bruin also is a past volunteer for the American Red Cross, Habitat for Humanity and Hunger Task Force.