Eugene grew up in an orphanage, didn't he? So he probably didn't know his parents.

I'm not counting Aladdin because he knew of his dad (yes he has a dad and he's one of Disney's Worsted Fathers) and I using Parentless lightly because...well Kristoff adoptive Family...well...yea.

Anyway I feel like Kristoff knew of his parents, because of the sled and Sven, I don't think an orphan could get his hands on those things if he was orphaned at birth.

I would say..

I'm guessing his dad was an ice-harvester and he came to work with them (with his own reindeer, sled, and tongs) because the ice harvesters knew his father and so let him tag along.

That's the one plot hole in the movie that bothered me, by the way. I thought, "Hey, finally a peasant man that woos a princess who didn't grow up like an orphan (like Aladdin and Eugene). I'll bet he even has a family and community in the ice harvesters. I can't wait to meet them." Then it turns out, ONCE AGAIN, we have an orphan. How original, Disney.

I always thought his dad was an ice harvester and found it weird that the trolls could've taken him from the ice harvesters if his parents were still out there.