Daniel K. Biss

Daniel Biss is the Democratic nominee for the open Illinois 9th District seat.[1][2][3] A mathematician by training, he served in the Illinois House and Senate, finished second in the 2018 Democratic primary for governor, and was elected mayor of Evanston in 2021 and re-elected in 2025; he won the crowded March 2026 primary, and his campaign website says he is running on rebuilding an economy that works for everyone and limiting corporate consolidation.[2][3][4]

Biss was born August 27, 1977, in Akron, Ohio, to a family of professional musicians, and attended Bloomington North High School in Bloomington, Indiana.[3] He earned a bachelor's degree in mathematics from Harvard University in 1998 and a Ph.D. in mathematics from the Massachusetts Institute of Technology in 2002.[2][3] He was an assistant professor of mathematics at the University of Chicago from 2002 to 2008 and a Clay Research Fellow from 2002 to 2007.[2][3]

After losing a 2008 bid for the Illinois House 17th District, Biss worked as a policy adviser to Gov. Pat Quinn beginning in 2009.[2][3] He served in the Illinois House of Representatives from 2011 to 2013 and in the Illinois Senate (9th District) from 2013 to 2019, chairing the Senate Human Services Committee in the 2015 session and the Labor Committee in the 2017 session.[2][3][4] He ended a 2015 campaign for state comptroller and endorsed Susana Mendoza, and in 2018 he ran for governor, finishing second in the Democratic primary with 26.7% to JB Pritzker's 45.1%.[2][3]

After leaving the Senate, Biss became executive director of the nonprofit Rust Belt Rising, which aims to train and support Democratic candidates in Great Lakes states, and worked as a clean energy consultant.[3] He took office as mayor of Evanston on May 10, 2021, and was re-elected April 1, 2025, with 62.7% of the vote.[3] In June 2026 he announced he would resign as mayor on October 18 to trigger a spring special election.[5] Biss announced his congressional candidacy in May 2025 for the seat of retiring Rep. Jan Schakowsky, who endorsed him in January 2026, and won the March 17, 2026 Democratic primary with 29.4% of the vote.[2][3]

Researched from the cited sources on 2026-10-21.