My name is ***** ***** I’ve been involved professionally with dogs in the health and behavioral fields for over 18 years. It will be my pleasure to work with you today.
It sounds like he needs more obedience training so he sees you, the owner, as the boss. It is the boss' job to protect the "pack" or in this case, your job to protect him. Obedience training establishes you as the boss and protector. It doesn't matter if he knows the commands, he needs to learn to obey you and see YOU as the boss. The following site is helpful in helping owners train their dog. Be sure and click on the link to the page on obedience at the bottom. and links on subsequent pages leading to detailed instructions.
Training works best if you train at least 30 minutes a day (two 15 minute sessions). I would start making your dog work via the Nothing in life is free program (NILF). It is outlined below.
It will be helpful if you can find someone with a dog that he will react to that will help you once you have your dog listening to commands consistently. What you will do is have your dog on the leash. You will have your helper off in the distance. Your helper will gradually move their dog a bit closer to you preferably walking past your position in the distance. As long as your dog ignores them, you can give your dog praise and a treat. The second you see harvey fixate on the other dog or show any other sign of aggression (hair standing up, etc.) give your dog a correction by giving a short tug and a firm low toned "NO". It shouldn't take your dog long to realize you will not tolerate the aggression and that if he ignores the other dog, he gets treats. Use hot dog slivers as treats. Once this happens you can repeat the training moving the other dog closer until he is no longer growling and barking at other dogs. You will need to practice this when you and your dog are walking as well.
The bat method may be helpful as well.
I hope this information is helpful to you. If you would like any additional information or have more questions please don’t hesitate to press the reply to expert or continue conversation button so I can address any issues you still have . If you do find this helpful, please take this opportunity to rate my answer positively so I am compensated for my time.