Rodriguez serves the 22nd Ward, which covers Little Village and other Southwest Side neighborhoods.
He said he wants to spend more time with his family.
"I am proud of what we have built together, because I want to be clear, it was never just me. It was us. It was neighbors who showed up to meetings, the organizers who knocked on doors, and the families who worked hard to build this community that made the victories possible," he said in a letter.
Rodriguez has been a major ally of Mayor Brandon Johnson, who has not yet announced his own re-election campaign.