Ayers and his wife, Bernardine Dohrn, spoke exclusively with NBC Chicago's Dick Johnson about why they joined the Election Night celebration in the park, where 40 years before they helped stage the Days of Rage riots.
The couple said they got last-minute tickets from a friend to be in Grant Park that night.
"I couldn't stop crying a couple of times. I found the exact spot where I was beaten 40 years ago," Ayers said. "But I've never been in a crowd that large that wasn't edged with either anger or drunkenness or gluttony, and it was really an extraordinary feeling."
Maligned as terrorists by Obama's opponents because of their activities in the late '60s, Ayers told NBC Chicago that he and his wife condemn all forms of terrorism. They prefer labels like activist and radical -- although these days, they're more likely to be called professor, or grandma and grandpa.
Ayers and Dohrn said they chose to stifle reaction to the way their activist past was dragged into the campaign rhetoric against Obama. But privately, they were as swept up in the history of the moment as all the rest who voted for him, and they believe some of what they did almost four decades earlier helped bring about Obama's election.
"Without the struggles of the 60s ... there would be no President Obama," Dohrn said.