He starred at quarterback for Notre Dame more than a half-century ago, before the Touchdown Jesus mural and even facemasks. He won three national championships and appeared on a Life magazine cover. At 91, he’s the oldest living Heisman Trophy winner and his name is Johnny Lujack.

To great-grandson Charley Flanagan, he’s just Baba.

Lujack will see Flanagan, a senior captain and tight end for St. Thomas Academy and the oldest of his eight great-grandchildren, play in a varsity football game for the first time Friday.

“It will be a big thrill,” Lujack said this week by phone from his home in Bettendorf, Iowa. He spends winters in California with Pat, his wife of 67 years.

“He’s a tight end so I don’t have much information for him,” Lujack said. “Just play tough.”

Flanagan, whose Cadets play host to Simley, said: “It’s definitely a special game for me. But I have to execute what the coaches tell me to do.”

So far this season, that has meant blocking; Flanagan has caught just two passes for the Cadets (1-2). But neither a lack of receptions nor victories has Flanagan down.

“We aren’t where we want to be, but being 1-2 doesn’t define our season,” Flanagan said. “We need to stay the course because we know we’re better than that.”

He learned resiliency watching his great-grandfather, who underwent spinal surgery at the Mayo Clinic in 2014. Numbness caused by spinal stenosis meant facing possible paralysis or undergoing a five-hour procedure, said Amy Flanagan, Lujack’s granddaughter and Charley’s mother. Intense rehabilitation followed surgery.

When Charley was just a month old, Baba held him for the first time. Now it was Charley’s turn. Gently placing his arm on Baba’s back to steady him, the two paced the hall of the rehabilitation floor.

“Even at his age, he felt he still had a lot of life to live,” Amy said. “He’s not a quitter, and that made an impact on Charley.”

Flanagan has long been enamored of his great-grandfather. They have attended Notre Dame football games together since Flanagan was 5 years old. Highlights include meeting favorite Irish players such as Giants pitcher Jeff Samardzija, who gave him gloves, and Kyle Rudolph, now a Vikings tight end.

Flanagan marveled at the scores of fans asking Lujack for a handshake, autograph or photograph. But the youngster also noticed the way he treated the staff at restaurants with respect.

“He’s just a kind, good person,” Flanagan said.

The lesson stuck. St. Thomas Academy coach Jason Sedlak called Flanagan “a positive young man who goes out of his way to pick up teammates.”

Lujack and Flanagan also share a love for competition across the athletic spectrum. Growing up in Connellsville, Penn., Lujack earned varsity letters in football, basketball, baseball and track and field — a feat he matched at Notre Dame. He won the Heisman Trophy in 1947 playing quarterback, defensive back and punter for the undefeated Irish.

Flanagan, 6-3, 210 pounds, plays varsity football and lacrosse. And he played goalie for the Cadets’ Junior Gold B hockey state championship team.

“I think it’s great whether he’s playing one sport or three or four,” Lujack said. “You’ve got to feel it in your heart.”

Lujack appeared on the cover of Life magazine 69 years ago this month, kneeling in Notre Dame’s green jersey and gold pants, and cradling a football in his right arm. Charley received a signed copy of that Life cover for his birthday five years ago that read: “To a great great-grandson. Love, Baba.”