Mr. Nern is a character in Hard Luck. He is a history teacher and always goes to the Find-A-Friend Station when someone pushes the button. He goes there when Greg pushes the button and asks to be his friend. Greg reluctantly agrees to play checkers with him, and when he lends Greg his oversized shoes after Greg got dog poop on one, Greg hopes he doesn't have to keep playing checkers with Mr. Nern. He is last seen going to Rowley Jefferson after he got dumped by Abigail and presumably played checkers with Rowley as well. He also is the teacher of the Board Game Club.
- Diary of a Wimpy Kid: Hard Luck (First and only appearance)