This article is rated G, meaning it is appropriate for all ages.
On Christmas Eve, the teacher hires Professor Hinkle, an inept magician, to perform for the children's Christmas party. After becoming uninterested in his tricks, the children go outside to play in the snow where they build a snowman with a corncob pipe, a red button nose, two coal eyes and a broomstick. After the children's suggested names for the snowman including Harold, Bruce, Christopher Columbus and "Oatmeal", Karen names him Frosty. Just then, Hinkle's rabbit, Hocus Pocus, hops outside with Hinkle's silk hat over him. By the time Hinkle also comes out and grabs Hocus, the wind then blows the hat until Karen catches it and quickly places it onto Frosty's head. And suddenly, to the children and Hinkle's surprise, Frosty transforms into a living snowman with an aura of sparkle, saying, "Happy Birthday!" The children becomes delighted as they realize it was the magic of the hat that cause Frosty to come to life. But after he also finds out that the hat is magic, Professor Hinkle takes back the hat when another wind blows it off Frosty's head, changing the snowman back to his lifeless form. The ridiculous magician vows to use the hat to become a millionaire, and when the children state their objections, he mockingly tells them that when they grow up, they'll learn that snowmen can't come to life and leaves.
However, Hocus steals back the hat from Hinkle by switching it with the pine-wrath and escapes his greedy master, immediately returning back to the children and Frosty. Thanks to Hocus, Karen puts the hat back on Frosty's head, and for the second time, the snowman is brought to life by its magical power. However, as the children had fun with their friend after observing him learn to speak more words, move his body, juggle snowballs, count numbers and express emotions like being ticklish, Frosty enters the early stages of sweating. Noticing a thermometer on the school's brick wall, he worries that when the temperature rises, he will melt. On Karen's suggestions to find some place where he'd never melt, Frosty names only one place: the North Pole. The children decide to take him to the North Pole, even taking him downtown to the railroad station where he can ride on the train. Frosty, the children and Hocus parade through town, shocking other people including the traffic cop who then accidentally swallows his whistle after excusing Frosty for being alive and naive. When the group arrives at the railroad station, however, they realize they have no money to buy train tickets. So Frosty, Karen and Hocus hitch a ride on a train headed north in a refrigerator car full of ice cream and frozen Christmas cakes. However, as the train departs from the station, Professor Hinkle also sneaks aboard, still vowing to get the hat back.
Noticing that Karen is freezing in the boxcar, Frosty realizes that she has to get out. And so, when the freight train stops to let a passenger train filled with Christmas travelers pass, Frosty, Karen and Hocus jumped off the car just before the train starts off again. Seeing the trio avoiding him, Professor Hinkle jumps off the train as well, but tumbles down the hill and hits a tree where snow and icicles fell on him while a nearby squirrel laughs at his fortune. Now in the woods, Frosty, Karen and Hocus struggle to get as far away before Hinkle could catch up to them, Karen is suffering from hypothermia, and the woods are bitterly cold. And to make matters worse, when Hocus suggests the need of building a fire, Frosty reveals that he can't do it. Luckily, the threesome finds the forest animals decorating their Christmas tree to await the arrival of Santa Claus. Frosty asks Hocus to tell the animals to build a fire for Karen. After the animals did so to let Karen warm herself, Frosty also needs someone to come bring her home and him to the North Pole. Both the ideas of the Marines and the President of the United States refused, Hocus suggests Santa. Frosty orders Hocus to go back to the animals and bring Santa to him when he appears. But that night, as Frosty waits patiently for Santa, the now-recovered Professor Hinkle shows up. He blows out the fire and demands Frosty to give him back the hat. Frosty and Karen escape Hinkle by sliding down the snowy hills at the fact that Frosty was the "fastest belly whopper in the world" after being made of snow. They both see a greenhouse used to grow Christmas poinsettias, and went inside where Frosty is beginning to melt very slowly. But the exhausted Professor Hinkle again catches up and closes the door behind Frosty and Karen, trapping them inside and ensuring that hat will be his again when Frosty is completely melted.
Meanwhile, Santa Claus arrives and Hocus leads him to the greenhouse where Professor Hinkle quickly hides behind the tree to avoided getting seen, only to find Karen crying over a melted Frosty. But Santa explains that Frosty is made of Christmas snow and will come back every winter. And to show Karen how he means it, Santa then opens the greenhouse door and lets the magical "December Wind" take out Frosty's puddle, restoring his body. But just as Santa, Karen and Hocus are about to put Frosty's magic hat back on to bring him back to life, Professor Hinkle reappears and still demands that he wants the hat back. But Santa warns him that if he takes it, he'll never get another Christmas present for the rest of his life. Professor Hinkle is upset at the fact that he may never have any more magic accessories, stating that "evil magicians" have to make a living as well. Santa suggests that if Hinkle writes his apologies a hundred-zillion times with the words, "I am very sorry for what I did to Frosty.", he'll get a new hat in his stocking on Christmas morning. Overjoyed in agreement, Hinkle runs home to write his apologies, saying goodbye to Santa, Karen and Hocus. Santa then brings Frosty back to life, and later on, he takes Karen home, and brings Frosty back to the North Pole, promising that he'll return next year.
As the end credits roll, Frosty, the children parade through town. The townspeople are also in the parade, including the traffic cop, and a reformed Professor Hinkle wearing his new hat. At the end of the parade, Frosty boards Santa's sleigh and they leave for the North Pole with Frosty altering the song's last lyric, saying, "I'll be back on Christmas Day!"
- Dan Aykroyd as Frosty
- Ed Helms as Professor Hinkle
- Valeria Cotto as Karen
- Debi Derryberry as Boy #A, Boy #B, and Boy #C
- Tara Strong as Little Girl and Little Boy
- Christopher Lloyd as The Narrator and Ticket Man
- Kath Soucie as Teacher and Karen's Mother
- Jim Cummings as Traffic-Cop
- John Goodman as Santa Claus
- Frank Welker as Hocus Pocus
- Hitor Pereia
- Pharrell Williams
- Frosty the Snowman Score Medley - Willie Nelson