The Simpsons: 10 Greatest One-Time Characters
3. Mr. Bergstrom
The Episode: "Lisa's Substitute" (Season 2, Episode 19)
The Voice Actor: Dustin Hoffman
It was Dustin Hoffman who perhaps gave Lisa Simpson her most emotional moment in the show's entire run - and all the way back in season two, no less! Hoffman provided the voice for substitute teacher Mr. Bergstrom, though was credited for his work on the show under a pseudonym, due to contractual obligations.
The Lisa/Mr. Bergstrom story is heartbreaking stuff, of course: Lisa, ever the outsider in a town full of slackers and morons, finds a kindred spirit in the funny and eloquent Mr. Bergstrom, who genuinely understands and cares. Unfortunately, he's a substitute teacher, and so it's his destiny to move on, never sticking to one place.
Put alongside the other, wackier characters in The Simpsons canon, Mr. Bergstrom felt like a relative obscurity. So it was undeniably heartbreaking when he finally left Springfield via train, informing Lisa she should refer to a handwritten note that read, "You are Lisa Simpson," whenever she felt like she was lost or alone in the world.
Just the thought of it is enough to get you choked up, and Hoffman's charming, understated turn sells the character - and his relationship with Lisa - perfectly.