Surgery on the 89-year-old Lujack was successful and he is doing "very well" Thursday, Mayo spokeswoman Duska Anastasijevic said. Amy Flanagan, Lujack's granddaughter, said he is in good spirits.
"He came through the surgery just great, telling jokes in the intensive care unit," Flanagan said. "He's so positive. He's already making great progress. But he's got a long road to go. He's got to be patient."
She said he had spinal stenosis that was causing numbness. She said he was brought from Genesis Medical Center in his hometown of Davenport, Iowa, to the Mayo Clinic by helicopter Monday and had surgery Wednesday. She said he risked paralysis if he didn't have the five-hour surgery.
"It was a pretty dire situation," she said.
The Fighting Irish won national championships in 1943, '46 and '47, with Lujack posting a 20-1-1 record as the starting quarterback. He missed the 1944 and '45 seasons while serving in the Navy during World War II.
Lujack won the Heisman in 1947 and was selected the athlete of the year by The Associated Press. He also was a first-round draft pick of the Chicago Bears. He played four seasons with the Bears, playing in the Pro Bowl his final two seasons before retiring at age 26.