Quinn, who has represented the 13th Ward since 2011, said the role of an alderman has changed significantly during his tenure.
"It is a different City Hall" than when he first took office, Quinn said, adding that his job representing the Southwest Side ward has changed "100%."
He said the City Council is no longer a rubber stamp body.
"Full legislative battles happen almost every week down here now, and I think that's healthy. I think it's a better; it's a better product for the taxpayer," Quinn said.
Quinn has been part of a faction of aldermen that has opposed Mayor Brandon Johnson and his allies on budget issues.
Despite policy disagreements with the mayor, Quinn said Johnson has made some strong commissioner appointments and cautioned against dismissing the mayor's reelection prospects.
"He has maintained relationships with some strong constituencies and continuing to grow those," Quinn said.
The 13th Ward, which surrounds Midway airport, includes neighborhoods Quinn described as home to bungalow residents, city workers, police officers and firefighters.
He called them "the backbone of the city."
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Quinn, 51, began his political career with the support of former Illinois House Speaker Michael Madigan, who is serving prison time for political corruption.
Quinn said he does not regret his relationship with Madigan.
"It's part of my history; it is who I am. I wouldn't be here if it wasn't for Mike Madigan," Quinn said.
Quinn said Madigan helped secure new parks and five new schools in the ward during the past 15 years.
Ald. Michael Rodriguez, whose 22nd Ward is also on the Southwest Side, praised Quinn's work ethic and commitment to residents, despite policy disagreements between the two.
"Marty Quinn and I disagreed on a lot of things, but we were never disagreeable. We always were willing to call each other and pick up that phone and tell it to each other straight," Rodriguez said.
Quinn said he decided not to seek another term because he has "left it all in the field."
Asked about his future plans, he ruled out a run for mayor.
"I'm not running for the mayor of the city of Chicago; I think my wife would kill me to even entertain that," Quinn said.
Petitions for Chicago's mayoral and aldermanic races begin July 28. Quinn has not endorsed a successor, but said his ward superintendent would be a good choice if he decides to run.