It turns out all you need to do to become Santa is to kill the current Santa.  To stay Santa, you just need to trick a frigid high school principal into marrying you.

Scott Calvin (Tim Allen) is a crappy father.  But after mostly ruining Christmas, he has the chance to redeem himself by putting on the suit of Santa Clause, whom he recently murdered.  Suddenly, he finds himself bound by a contract he didn’t see to permanently become King Christmas himself.

Several elves (disguised as crappy child actors) explain all of this to him and all his problems as a father disappear.

Eight years later, in “The Santa Clause II”, we learn about another clause of this totally-not-legally-binding contract: he needs to get married.  Fortunately, he’s able to use his santa-magic to make it seem like there’s chemistry between him and Elizabeth Mitchell from “Lost”.  And something about an evil toy-santa dictator.  I’ve forgotten.

Like most Christmas movies, everything is about the children and Christmas is saved.  Unlike most Christmas movies, these both have lots of reindeer farting.