Crowds below cheered on the seventh-generation aerialist, who wore a microphone during his untethered walk. The "Skyscraper Live" walk was broadcast on Discovery.
"I love Chicago, and Chicago definitely loves me. What an amazing roar," the 35-year-old said as he crossed above the Chicago River.
The walk consisted of two parts, starting from Marina City's West Tower, about 588 feet high. He crossed above the Chicago River to the Leo Burnett Building in just under seven minutes, finishing 671 feet above the street, according to Skyscraper Live's website.
After he returned to the West Tower, he crossed to the East Tower blindfolded in one minute and 20 seconds.
As a member of the famous Flying Wallendas, founded by his grandfather Karl Wallenda in the 1920s, Wallenda is no stranger to death-defying stunts. He walked across a wire 1,500 feet above a river in Arizona in June 2013, becoming the first person to traverse the gorge near Grand Canyon National Park in Arizona. Before that, he made a record journey across Niagara Falls in 2012.
Peril also runs in the Wallenda family. Great-grandfather Karl Wallenda was killed at 73 while attempting to walk between two buildings in Puerto Rico in 1978.
But on Sunday, Wallenda made it look easy.
"I'm so blessed for these opportunities," he said during his walk. "You guys watching think I'm crazy, but this is what I was made for."