Mark Spreitzer was sworn in as the State Senator for the 15th Senate District on January 3, 2023. In November 2024, Mark was elected by his colleagues to serve as the Senate Democratic Caucus Chair for the 2025-2026 legislative session.

During the 2025-2026 legislative session, Mark serves as the ranking Democratic member on the Committee on Government Operations, Labor, and Economic Development, and as a member of the Committee on Agriculture and Revenue and the Committee on Transportation and Local Government. 

During the 2023-2024 legislative session, Mark served as the Senate Democratic Caucus Vice-Chair and the Chair of the Legislative LGBTQ+ Caucus. In 2024, he was selected as one of 20 state leaders to receive the Council on State Governments 20 Under 40 Leadership Award. 

Mark previously served as the State Representative for the 45th Assembly District from 2015-2023 and served as the Assembly Democratic Caucus Chair from 2016-2022. Prior to serving in the State Assembly, Mark served for four years on the Beloit City Council, including as Council President. 

Mark is an active member of the community and participates in nonprofit and community organizations, including serving as a Board Member of the Welty Environmental Center and on the Finance and Facilities Board of the United Church of Beloit.

Mark lives in Beloit with his husband Philip, their cat Otis, and their backyard chickens. In his free time, Mark enjoys the outdoors and attends events across the 15th Senate District. 

Senate Committees: 

• Committee on Agriculture & Tourism
• Committee on Government Operations, Labor, and Economic Development 
• Committee on Transportation and Local Government
• Board Member, Wisconsin Housing and Economic Development Authority (WHEDA)

Leadership Positions:

• Senate Democratic Caucus Chair
• Wisconsin Legislative LGBTQ+ Caucus Chair