Does Santa Claus really need an origin story? Isn't part of the wonder of Santa Claus that he's just there, that he doesn't have to be explained or justified? I might not have much cared for Miracle on 34th Street, but at least it doesn't spend all its time patching continuity holes about why its main character is Santa Claus and how he can do what he does. He is Santa because he is. That's all we need to know.
Clearly producers Alexander and Ilya Salkind didn't agree, because after spearheading three Superman movies and one Supergirl movie, they decided that the next mythical figure who deserved the epic treatment was Santa Claus, so they set up a film that bears remarkable similarities to 1978's first Superman movie. David Huddleston (yes, the Big Lebowski himself) plays Santa, who starts out as your average 14th-century peasant with a bushy beard and a love of children, for whom he makes hand-crafted wooden toys to hand out every year on Christmas. He's so dedicated, in fact, that he and his wife and their two reindeer (named Donner and Blitzen) nearly freeze to death in a snowstorm while trying to make it to one more house. Luckily they are saved by a magical race of elves called the Vendequm, who have been waiting for centuries for the prophesied chosen one to come along and lead them in their quest to deliver toys to all the children of the world.
We get about 40 minutes of this Santa Claus Begins stuff, as the movie shows us the origin of Santa's workshop, his red outfit, his sleigh, his list of naughty and nice children, etc. Then, once we catch up to the present day, the movie abruptly introduces a couple of lovable orphan characters in New York City, who'll become Santa's helpers as he has to face off against an evil toy manufacturer (John Lithgow, overacting like there's no tomorrow as the equivalent of Gene Hackman as Lex Luthor) and bring to heel a rogue elf (Dudley Moore) whose assembly-line ideas about toy production have resulted in shoddy product from Santa's workshop.
In case you couldn't tell, this is a really weird movie, one which wants to take Santa Claus deadly seriously but also wants to be whimsical fun for children; which waits an hour before introducing its major villain; which is full of stupid puns like "elf-assurance" and "elf portrait" but also creates a fantasy novel-esque mythology for the little creatures who help Santa. It uses creepy animatronic reindeer, blatant and crass product placement, and actors who are clearly of normal height to play elves. It pretty much ended the Salkinds' careers as movie producers, and it's not hard to see how that happened. Santa Claus isn't Superman, and this movie proves exactly why.
The True Meaning of Christmas: Don't fuck with Santa Claus.