He had a very interesting record as an NFL player - the only Bears QB to throw for more than 5 TDs in a game (he threw 6) until Mitch Trubisky tied him in '18.
He was Leahy's pick as a successor at HC, but Terry Brennan got the nod from the president at the time. He never coached again, and we'll never know if the lost decade between Leahy and Parseghian would have been different with Lujack at the helm. Honestly, it probably wouldn't, because the ND administration at the time was actively sabotaging the football program by implementing scholarship limits that did not exist elsewhere in college football to improve ND's image as an educational institution vs. a football one.