- "I started panicking. People got hurt."
- ―Cannonball describing the first time his mutation manifested
Samuel "Sam" Guthrie is a young boy from Kentucky. He had a close bond with his family who were coal miners. Sam eventually got a chance to work with his father, Thomas, and his fellow miners one day, but the unfamiliar environment and claustrophobia caused him to suddenly cause a cave in with his explosive jet propulsive mutant powers. Sam was the only survivor and found himself on the run from authorities. He was found by Dr. Cecilia Reyes who offered him a safe haven at the hospital she was keeping other mutants with uncontrollable abilities in the hopes that he can somehow master his powers. Sam started to train and control his abilities by strapping himself to a harness tied to an anchor and flying around in the courtyard; resulting in him getting slightly injured and bruised. He becomes the first to experience the strange visions and begins to suspect that they have something to do with his inability to control himself and starts to panic.
When the Demon Bear arrives, he protects his friend Dani Moonstar and eventually decides to fight the creature telling Roberto da Costa "Gotta get better some day." After Dani defeated the Demon Bear, Sam notices that the barrier protecting the hospital is gone (Dr. Reyes was killed earlier) and he and the rest of his friends step out into the road to find a new home.
To be added
- Thermo-Chemical Energy Field Propulsion: Cannonball possesses the ability to generate thermo-chemical light-purple energy from his body. This energy is used as thrust to cause his body to be propelled through the air, like his namesake, at great heights and speeds.
- Blast Field: This energy also manifests itself as an impenetrable and virtually indestructible "blast field." He can use this blast-field to function as a personal shield or extending it to encompass others, shape the field around another person to imprison them, or absorb outside kinetic impact into his own energy supply and then re-channel it to increase the bludgeoning power of his blows or create explosive shock waves upon impact. Sam is also capable of generating the blast field without actually having to blast off, though it takes him extreme concentration to prevent himself from propelling into the air
- Flight: Sam is able to fly while using his mutant abilities.
- Superhuman Strength: When he is using his powers, Cannonball possesses superhuman strength due to the energy field that forms around his body allowing him to generate additional force.
- Superhuman Durability: When he is using his powers, Cannonball possesses superhuman durability due to the energy field that forms around his body insulating him from outward impacts and collisions.
- Sam's Coal Stone - A gift from his dad.
- Cannonball's real name, Samuel Guthrie, appeared on the Department of Domestic Security and Defense computers in X2: X-Men United. His name was listed alongside Paige Guthrie, who is Cannonball's younger sister in the comics.
- In the novelization for X-Men: The Last Stand, Cannonball was one of Wolverine's students.
- Cannonball was supposed to appear in Deadpool, but was replaced by Negasonic Teenage Warhead due to the character's eye-catching name.
- Cannonball's creator, Bob McLeod, was unhappy that the character was not "tall and gawky" like in the comics, though he did like Charlie Heaton's performance.