Your cat is not use to the new scent in the house and cats relay heavily on their sense of smell. Try to keep the new kitten in a room for a few days along with his litter box, food and water and put your other cat in another room. After a few day, switch rooms so they each can get familiar with the other's scent.
You can try to do this - Make sure that all doors are open and you have a squirt bottle in case things don't go well. While talking to them in a very soft, calm voice, wrap a towel around both of them then put them nose to nose and let them sniff each other. Continuing to talk to them. If this goes well, put your male kitty on the floor without the towel and let him sniff the kitten while he in still in the towel. If this goes well, try putting kitten on the floor and play with him, so big kitty can watch and see that the kitten is harmless. Keep watch for any signs of aggression. Take your time letting them get to know each other.
Some other things you can try is rub tuna juice on both of your cats' head and shoulders to hopefully encourage them to groom each other. Distract your male cat with a flash light or laser light if you sense that he is going to react in not a good way. Give kitty nip to at least your big cat if not both. Also, using a Feliway Plug or Spray (which is a natural substance, odorless to humans, that mimics a cat's facial pheromones to calm cats in stressful environments) to keep both cats calm. Give them a treat, praise, cat nip or any kind of positive feedback, when they are getting along. Keep a water sprayer available just in case.
Just be patient, they will eventually accept each other once he realizes that kitten is staying. It would be a good ideal to keep their litter box, food and water separate for a little while until you feel they have accepted each other. Good luck, I hope everything works out for the best.