Cannonball possesses the ability to bodily generate thermo-chemical energy and release it from his skin. This energy is used as thrust to cause his body to be propelled through the air, like his namesake, at great heights and speeds with considerable maneuverability. He can control his speed and direction through sheer act of will. At first he could only release this energy from his feet and legs, but now he can fire it from almost any part of his body, to a wide variety of effects. 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. For example, in the final episodes of the 90's X-Men Animated Series, Cannonball flew head on to stop a freight train and derailed it without effort.
His power levels have varied over the years - but at his peak, he has been able to devastate several city blocks by plummeting to the ground from high altitude, as well as withstand (and redirect) the force of one of the Gladiator's strongest punches. As of now he is the first and only X-man to ever defeat Gladiator. [7]
He is also a member of the immortal mutant group the Externals, due to his apparent ability to return to life after death. Whether this would happen if he died again is unclear.