I understand completely doing something you horse loves to do, but jumping is a serious ‘leap’ (please forgive the pun) in training if the canter is not under control. I would start by doing some ground work with him. Try lunging him at the trot and canter so he can learn what the three beat gait feels like. When lunging add a kiss or vocal signal to associate with the canter. Once he understands on the ground what the step is then bring it to the saddle and attach the vocal cue to the leg cue. He should be able to quickly connect what he was doing on the ground to what you are asking for in the saddle.
When you work on the canter take the jumps out of the equation. You want him to feel comfortable in the gait before you add another element. If he bolts forward out of the trot into the gallop transition him back down to the trot and try again. Don’t stop him until you get at least four steps into the canter. Then stop, pat him(reward), and change directions. Let him figure out what he is supposed to be doing. If you have started on the ground first the learning curve should be fairly quick.