Continuity mistake: When Rudy thanks his employer for the key and the blanket, each shot that faces Rudy you can see a large amount of snowflakes falling. However, whenever the shot faces his employer there is only an occasional snowflake that falls. (00:53:40)
Continuity mistake: When Rudy opens one of his rejection letters, he checks his mailbox and heads to a cafe. This cafe is in a building on the actual Notre Dame campus, has no student mailboxes in it, and is not the Holy Cross College campus where his mailbox should be. (00:59:15)
Continuity mistake: When the team captain comes in to talk to the coach about giving up his spot for Rudy so Rudy could dress, the coach has a clock/pen and pencil set at the front of his desk. However, when the captain and all the other players lay their jerseys on the desk, the pen and pencil set is gone. (01:33:30)
Continuity mistake: When the players start coming in to hand in their jerseys, you see a few of them come in from the front view. Watch the numbers of the jerseys - as it switches views the numbers start to repeat. (01:34:05)
Continuity mistake: In the scene that takes place right before the big game with Georgia Tech (the game Rudy plays in), the stadium shows the Penn State Blue Band on the field playing the Penn State fight song. The game then starts and Notre Dame is playing Georgia tech. (01:39:20 - 01:41:00)
Continuity mistake: In the scene where #75 starts chanting "Rudy" on the sideline, the next scene shows him out on the field blocking. Then, the very next scene he is chanting "Rudy" on the sidelines again. (01:44:00)
Continuity mistake: When Rudy goes to speak Coach Ara to beg him to play the only blemish on his face was a cut above his right eye. But that night when Rudy calls home the cut is now above his left eye.
Continuity mistake: When Notre Dame are huddling up on the field right before their final game, Coach Devine is giving his pep talk with his back facing Rudy. The very next shot, he's done a complete 180 and is now facing Rudy.
Continuity mistake: In the bar scene when Frank turns around and pushes Pete, you can see Rudy's dad get out of his bar chair in the background. Two shots later he is seated and then gets out of his chair again.
Answer: According to the Trivia section (as well as some web searching) it seems to be Peter Rausch, an ex-Notre Dame football player.