[2] Most notably Kelly Cassidy was the chief sponsor of House Bill 1438, making Illinois the first state to legalize the Adult-Use of Cannabis through legislature as opposed to a ballot measure.

In the 2012 Democratic primary, Cassidy was challenged by Paula Basta, a lesbian and longtime North Side activist.

The position became vacant after incumbent Joe Moore stepped down, following his defeat in the election for 49th ward alderman to Maria Hadden.

[15][16] In February 2021, State Sen. Heather Steans, who was re-elected just two months prior to represent a district covering Rogers Park, Edgewater, and Andersonville, resigned, having suddenly decided that “it's time for new faces and fresh energy.” A replacement in such a situation is picked by the district's committeepeople: an unpaid County-level position elected during presidential or gubernatorial primaries.

Despite being the presumed front runner and endorsed by the outgoing State Senator, Cassidy lost the vote of committeemen to Rahm Emanuel's former policy director Mike Simmons.

Community groups protested what was seen as an attempt by the State Representative Cassidy and Senator Steans to circumvent the normal election process as had been done several times previously in that district.