I'll be honest I've never heard of him. My absolute fave is Susan Garrett, but others include Kathy Sdao, Susan Salo, Ken Ramirez, Karen Pryor, and Sue Ailsby. I'm sure there are like 100 more, but those are off the top of my head.
Brandon Macmillan has a show on CBS Saturday Morning called Lucky Dog. Each episode involves Brandon taking a shelter dog and training him/her in what he calls the seven basic commands and whatever else a specific prospective owner/family might need (e.g. for a professional photographer who wanted a dog he could take to his studio, he not only taught the dog good shop manners but taught him how to "hit his mark" so his photo could be taken easily--that particular dog turned out to be a natural ham who was up for wearing costumes, dealing with props etc. which delighted his new owner). I do like that he emphasizes the ideas that you can get a good dog at a shelter, that adopting an adult dog can be a great idea, that all dogs should have basic obedience training, and that it's important to match specific dogs to specific families. He says repeatedly in his shows that if such-and-such doesn't work out, then this particular owner/family and this particular dog won't be matched up. Of course, in the interest of the show, that doesn't happen--they work the episode around dogs and families/owners that mess--but I like that he's firm about that without making it seem as if a dog is unadoptable or that a family/owner is a bad prospect just because a particular match wouldn't work out. They also show someone from a landscaping firm that specializes in providing dog-friendly spaces checking out homes and explaining about proper fencing, flowers, landscaping etc. In a half an hour, the show manages to provide a lot of information for dog owners, some of it pretty basic, but some of it likely less well-known, and while it's aired during Saturday morning programming that's meant to be kid-friendly, it's not all cutesy and kidsy, so it works for adults too.
Apparently Brandon Macmillan also helps train service dogs for veterans. In fact, he founded an organization to do that. One of his episodes of Lucky Dog dealt with training a service dog for a particular veteran, quite a young man who had lost either one or both legs (I can't remember which). Brandon trained the dog to, among other things, help him climb stairs, and on the first try, the guy refused to stop at just a few steps. He just looked at the dog and said, "C'mon, we can make it to the top," and then he and the dog went up to the top of quite a long outdoor staircase in a public park. When he got to the top and hugged the dog, he was crying, the guy's parents were crying, Brandon was crying...the only one who wasn't weeping was the dog.