Before Jack Frost became an immortal being who has the power over of ice and snow, Jack was a human boy who had a sister 300 years before the current timeline.
Jack has the appearance of a teenager and is considered good looking. He has silvery-white hair in spikes, but has black eyebrows and striking blue eyes. His skin is very pale but has somewhat of a blush to it. Tooth and her mini-fairies are considered to have a crush on him because of his good looks and teeth that "sparkle like freshly fallen snow". He wears a blue hoodie with frost designs and brown pants. He is always barefoot. Before Jack became Jack Frost he wearing a brown cloak a white woolen shirt and brown open vest. He also wore the same brown pants.
Normally, Jack Frost is a fun-loving, lighthearted, high-spirited, rebellious, wise-cracking, and mischievous trickster who likes to play games. He is quick to smile and laugh, and is at his happiest when he’s enjoying life, especially with other children.
He generally tends to be impulsive and thoughtless about his actions. Because of this, many of his pranks often wind up creating enormous trouble for other people, even to the point of becoming dangerous. Despite his careless behavior though, it is clear that Jack's intentions are benign, and he means no real harm.
In truth, his capacity to care for other people, particularly children, is very strong, and he also has a deep sense of what’s right. These traits become more apparent throughout the movie, as Jack goes out of his way to help the other Guardians.
In spite of his cheerful and devil-may-care attitude however, this exterior hid a sense of emotional fragility in Jack. Although it’s not obvious at first, hundreds of years of being by himself took a toll on Jack Frost. Since he couldn't be "Seen" by humans, he was virtually alone even in the midst of company. This fact became a primary source of pain and sadness for Jack, to the point where he feared being alone for all of eternity. Worse, he feared never knowing why.
This extreme sense of loneliness is mainly the reason for his resentment towards the other Guardians as well as the idea of becoming like them. However, it is for the same reason that Jack’s disregard for their opinion changes to wanting to be liked by them once they began warming up to each other. This longing grows to the point where he begins to fear not being accepted by them.
In the film, Pitch Black tormented Jack about these fears, playing on them in an attempt to get Jack to join him. However, Jack refuses the offer, not wanting to be hated by the world. Additionally, once Pitch is defeated and children start believing in him, Jack’s fears are ultimately abated, and he is able to bring Fun to the world in peace.
- The legend of Jack Frost came from Norse mythology. His other names are Father Frost, Old Man Winter, and Jokul Frosti (Icicle Frost).
- He caused a blizzard in '68 on Easter Sunday, resulting in Bunnymund holding a grudge against him.
- Jack has tried multiple times to break in to North's workshop, but he couldn't get past the Yetis; most likely the yeti known as Phil since Jack knows his name.
- Jack was originally from early, early colonial times before he became a "Guardian."
- According to the Rise of the Guardians app, Jack likes the beach - but only to have fun freezing waves.
- Jack is the only character who doesn't remember his past after being chosen as an immortal.