The Hobo is first seen under one of the Polar Express' passenger cars while Hero Girl's ticket is being blown underneath the train.
While trying to return Hero Girl's ticket, Hero Boy first meets the Hobo preparing coffee on a campfire on the roof of the observation car. He explains the situation to the Hobo, saying that he is looking for a girl, but the Hobo laughs, thinking he was talking about a romantic partner. Hero Boy shows him her ticket, which he recognizes the significance of and suggests he puts it in his slipper. He also claims that he always rides the train without a ticket and that he is the king of the North Pole. He also offers Hero Boy a cup of his coffee, but he spits it out after finding out that he washes his socks in it. After that, he questions the Hobo being the king of the North Pole, thinking Santa Claus would be more likely to hold that position, which leads to the Hobo putting on a Santa hat and mocking his laugh. After that, asks Hero Boy why he is going to see Santa, to which he replies saying he wants to believe. The Hobo then starts hinting that the events are just a dream, leading to Hero Boy to try to wake himself up by throwing snow at his face.
The Hobo then picks up Hero Boy and puts him on his shoulders, saying that they need to get to the locomotive before Flat Top Tunnel due to its roof being only one inch above the train's roof. However, the train begins going up a hill, causing them to nearly fall towards the rear. The Hobo stops himself by using one of his ski sticks to grab onto a handle, but Hero Boy falls off and ends up hanging from the edge of the car. The Hobo uses his other ski stick to lift him back and land him on his skis right in front of him. Next, the train begins going down the hill and the Hobo and Hero Boy ski down the passenger cars, jumping from one to the next. Right before the tunnel, Hero Boy manages to jump into the coal tender right before the train enters the tunnel, but the Hobo disappears.
Later, while the train ends up on the Ice Lake, it hits an iceberg which causes it to tilt and Hero Girl to almost fall off. Luckily, the Conductor and Hero Boy are able to catch her, but they cannot pull her back to safety until the Hobo appears and helps. He disappears before anyone other than Hero Boy got a chance to see him.
While the children and the Conductor were making their way back to the passenger cars, they walk through the abandoned toy car. There, the Hobo uses an Ebenezer Scrooge puppet, while hiding from the roof of the car, to scare Hero Boy, who quickly runs back to the other cars.
The Hobo appears again while Hero Boy, Hero Girl and Billy were in the runaway observation car. While they were looking for an emergency brake, Hero Boy finds the Hobo tapping on the car's brake wheel before disappearing again. Hero Boy turns the brake wheel and stops the car right before it crashes.
The Hobo makes one last appearance near the end of the movie, waving goodbye at Hero Boy from the roof of one of the cars after he gets dropped off at his house before disappearing one last time.
The Hobo is one of many characters in the film to not be from the book.
In the deleted scene, "It Takes Two," Smokey and Steamer tell Hero Boy and Hero Girl a story about the Hobo. A long time ago, the Hobo decides to ride on the roof of the train one Christmas Eve, but ends up getting killed after the train goes through Flat Top Tunnel. Some say that his ghost can still be seen riding the train every year. Had this scene not been cut, this would have confirmed that the Hobo is a ghost.