Democrat · Illinois's 9th District · 2026
Daniel Biss
Biss moved from a mathematics classroom into politics after joining protests against the Iraq War.
Biography
Daniel Biss grew up in Bloomington, Indiana, and lives in Evanston with his wife, Karin, and their two children.1 Karin is a former Peace Corps volunteer and a professor at National Louis University.1 His Senate farewell resolution noted another skill: juggling flaming objects.2
Biss earned a mathematics degree at Harvard and a mathematics Ph.D. at MIT before joining the University of Chicago faculty, where he worked from 2002 to 2008.2 His campaign traces his move toward political activism to opposing the Iraq War and organizing for progressive candidates.1 He entered the Illinois House in 2011 and later served in the state Senate.2
His legislative work included helping create Illinois Secure Choice, a retirement savings program for private sector employees.2.3 The program was designed around payroll deductions into portable individual retirement accounts for employees of private businesses.3 Biss was elected Evanston mayor in 2021.1 His final day as mayor was October 18, 2026.4 During his mayoralty, the city launched CARE, a civilian response program for selected low risk calls, including mental health concerns and wellbeing checks.5
Biss is the Democratic candidate for the 9th District.6 His platform supports Medicare for All, more housing near transit, lower childcare costs and action against corporate concentration and price gouging.6 He calls for abolishing ICE, modernizing the visa system and creating a citizenship pathway.6 He also supports a wealth tax on billionaires and taxing investment income like wages for people earning more than $1 million annually.6
Record and controversies
Acknowledged relationship with a former student
In March 2026, Biss's campaign acknowledged that he dated a former University of Chicago student in 2004, when she was 20 and he was 26.7 Both accounts placed the dates after his course ended; she described the relationship as inappropriate and characterized his conduct as grooming.8 His campaign said the dates lasted a few weeks, preceded his marriage and ended when he recognized that the relationship was ill advised.8
Retracted mathematics paper
A 2017 notice in Topology and Its Applications retracted a 2002 paper by Biss after independent review identified ambiguous definitions and incorrect results.9 The journal's editors explicitly clarified that the errors were inaccuracies, not fraud; Biss said he had left mathematics, could not fully evaluate the criticisms and did not dispute a retraction.10