Jamie is a child who strongly believes in the Guardians, Rise of the Guardians.
Jamie first appeared when Jack returned to Burgess to give it a snow day. Jamie is seen reading a book until the wind blows it away. Jack finds the book interesting and asks Jamie about it, but Jack knows that he can't be seen by Jamie. Jamie's friends Caleb and Claude rushed to Jamie and tells him about them having a snow day and Jamie asked them if they were going egg hunting on Sunday.
Jack followed Jamie to his house listening to their conversation. Jack knows Jamie is a believer in the other Guardians and find it offensive when Jamie's mom bring "Jack Frost nipping at his nose" to which Jamie asked Who is Jack Frost?" and his mom responded No one it's just a expression". Wanting to have a little fun with Jamie, Jack throws a magic snowball that hits Jamie in the back of his head and causes a snowball fight between him and his friends. When Pippa accidentally hits Cupcake, everyone gets afraid. Jack, wanting to continue with the fun, hits her with a snowball, changing her attitude from mad to happy which starts a game of chancing. The ground was slippery making Jamie fall in his sleigh and skate to the traffic. Causing Jack to make a snow path around the moving traffic and help Jamie returned to the park where Jamie flies so high that he goes over the status of Theddeus Burgess. Jamie, excited, asked his friends if they saw that before getting hit by a sofa which he then revealed that he lost a tooth causing the conversation to changed to the Tooth Fairy. Jack tried to remind them about the fun they have but gets sad when Jamie goes through him.
Jamie is later seen by Jack that night when he tells his family about the fun adventure he had and the new drawing he made. He also tell them about the tooth and planning on seeing the Tooth Fairy.
Jamie later appeared when Tooth and Jack have returned to get his tooth and leave a present. The Guardians all gather in his room but caused an uproar causing Jamie to wake up and see them (except Jack). Jamie's dog, Abby, starts growling at Bunnymund and Jamie tries to stop her. Jack wanting to mess up with Bunnymund, makes the alarm go off causing Abby to attacked Bunnymund and make him jumped around the room. Sandy, trying to put Abby to sleeps, which ends wth him hitting everyone except Jack, Jamie and himself. Jamie jumps out of bed when North lands on it and Sandy catch him. Sandman put Jamie to sleep and then goes to fight Pitch's Nightmares that have appeared with the help of Jack.
The next morning, Jamie is trying to find the eggs hidden by Bunnymund and he doesn't give up when his friends do. He tells them about he meeting the Guardians but they just tells him that it was a dream and that he should be happy he gets those and not Nightmares. Jamie is later left alone when his friends go home.
That night Jack rushed to Jamie's house to get him since he's the last believer in the world. Jack finds him talking to his stuff bunny and that if his real (Bunnymund) to give him a sign. Jamie seems to start losing hope in the Guardians until Jack makes an egg in his window. Getting Jamie's attention, Jack makes a bunny and makes the bunny come to live and jump around the room. Jamie gets excited and starts jumping in his bed until the bunny turns into snow causing him to believe in Jack Frost. Jamie asked "Jack Frost?" which caused Jack to look at Jamie and wonder if Jamie believed it him. When Jamie revealed he can see and hear him, Jack gets excited about having his first believer. When they hear North's sleigh, both of them rushed outside. Jame revealed he can see Jack and the other Guardians are pleased and Bunnymund thanks Jack for making Jamie keep his believed in him.
When Pitch appeared, Jack goes to fight him, making the other Guardians take Jamie away. Pitch being more powerful than before beats Jack and make him fell to the ally where the others where. Pitch trap the Guardians and Jamie there which make Jamie revealed that his afraid. Hearing that, Jack gets a memory of the same thing his sister have said causing Jack to learned what his center is (Fun). Pitch approached them but was hit by a snowball taking that a distraction they escape and go to reunited Jamie's friends.
With the help from the other Guardians, Jamie's friends believed again. Pitch find that amusing and asked them who going to protect the Guardians if the Guardians are protecting them. Jamie volunteered to protect the Guardians causing his friends to joined him. Pitch send a wave of nightmare sand their way but ones Jamie revealed "I do believe in you. I'm just not afraid of you." Jamie was able to turned the nightmare sand back to dream sand. Which helps the Guardians get their full energy back and battle Pitch. While the Guardians battle Pitch, Jamie got an idea on how to revive the Sandman.
The Sandman returns at the last second saving Jack from Pitch and he used his sand to give everyone good dreams and make more believers. While everyone were having a good time, Jack hit Jamie with a snowball which caused them to have a snowball fight. Pitch tried to make Jamie be afraid again but found that Jamie was not scared of him anymore and he's able to pass through him.
Pitch, afraid, retreats to his liar which caused the Guardians to followed and confronted him one last time. After Pitch was taken away by his own Nightmare, the Guardian ceremony was performed. Jack looked at Jamie which caused him to node and Jack said "I do" confident of making the right decision and making him a Guardian. The Guardian said they have to go making Jamie asked Jack if he was leaving.
Jamie Bennett: "You're leaving? But what if Pitch comes back? What if we stop believing again? If I can't see you..."
Jack Frost: "Hey, slow down, slow down. You telling me that you stop believing in the Moon when the Sun comes up?"
Jamie Bennett: "No."
Jack Frost: "Okay, well, do stop believing in the Sun when the clouds block it out?"
Jamie Bennett: "No."
Jack Frost: "We'll always be there, Jamie. And now we'll always be here." (points to Jamie's heart) "Which kinda makes you a Guardian, too."
Jamie gave him a hug which shocked Jack but then he returned the hug. Jamie wave at Jack and The Guardians good bye while they left.