Ditka's decision, announced at an impromptu news conference in front of his Chicago restaurant after a party fundraiser Wednesday, said he's not willing to give up his endorsements and committments to run.
That leaves the Illinois GOP still searching for a candidate to replace nominee Jack Ryan, who withdrew three weeks ago after sex club allegations in his divorce became public.
"Five or six years ago I would have jumped on it and I would have run with it, and I know this, that I would make a good senator, because I would be for the people," Ditka said.
The 64-year-old former Super Bowl-winning Chicago Bears coach had won endorsements from some party leaders relishing the media frenzy over his possible entry into the U.S. Senate race.
Celebrity Families of 2014 [PHOTOS]