The endorsement was announced Thursday morning at an event in Hyde Park.
RELATED: Longtime US Rep. Bobby Rush, Illinois legislator, will not seek reelection
Reaves is the CEO of the Chicago Cook Workforce Partnership, an umbrella organization that pairs businesses with job seekers. She announced Sunday that she was throwing her hat in the ring for the 1st District seat.
WATCH: Political analyst weighs in on Bobby Rush endorsement
Political analyst weighs in on Bobby Rush endorsement
According to a statement, Rush and Norington-Reaves first met in 2014 after a beloved teacher, Dr. Betty Howard, was killed by random gunfire in Chatham.
"I know in my heart and spirit that Karin Norington-Reaves is the person best suited for this responsibility," Rep. Bobby Rush said in a written statement.
Rush announced last Thursday that he would not seek another term after serving in Congress for the past 30 years.
After Rush's announcement, Alderman Pat Dowell dropped out of the race for Illinois Secretary of State and announced she was going to run for Rush's congressional seat instead.