Professor Hinkle is the antagonist of Frosty the Snowman. He is a magician hired to perform at the school's Christmas party. The narrator describes him as the worst magician in the world, as shown when his equipment fails and whose tricks go awry; he is shown sticks eggs into his magic hat, which all fall on the floor, and he fails to pull his rabbit, Hocus Pocus, out of the hat. He has a tendency to repeat adjectives and adverbs when excited or stressed, such as "Messy, messy, messy," or "Busy, busy, busy!"
After Hinkle's failed attempt at a magic show, the students to whom he was performing put Hinkle's magic hat on Frosty the Snowman, whom they had just created, and the hat brings the snowman to life. Seeing its magical properties, Hinkle takes the hat back along with the rabbit, hoping to become rich through use of the hat. However, Hocus escapes with the hat and takes it back to the children, who once again revive Frosty. When the children decide to send their friend to the North Pole so he can't melt. The Professor chases them on the train they are traveling on and vows to get the hat back.
Hinkle gets lost in the woods after a mishap on the train, but eventually catches up with Frosty and Karen, his friend who accompanied him on the trip up north. He ruins their campfire and demands the hat back, only to watch the two run off where he couldn't catch them. The two reach a greenhouse so they can warm up, but Hinkle catches up and locks Frosty inside, causing him to melt. Fortunately, Santa Claus arrived and was able to revive Frosty, but was confronted by Hinkle, who once again demanded the hat. However, Santa refused to let him touch, as it now belonged to the inanimate Frosty. Santa said Hinkle would receive no more Christmas gifts if he keeps on pursuing to get the hat, but told him that if he wrote an apology to Frosty a hundred zillion times, he might still receive a present of forgiveness. Realizing that this mean of a new hat he could use, Hinkle eagerly agrees, apologizes for the troubles, and runs off to get busy writing.
Hinkle appears during the credits marching along with Frosty's friends, donning a brand new hat, which means that he has already wrote up his apologies and Santa has kept his word. Hinkle is last seen tipping his new hat as he and the others bid farewell to Frosty, who is leaving with Santa, promising to be back on Christmas Day.