With his good looks, sultry crooning voice, and crowd-pleasing personality, Mad Dog Craddock's got everything it takes to become the 1930s version of Michael Buble. He's definitely got Arley Wanderdale's attention… and Billie Jo's too. While the Oklahoma panhandle isn't the first place you might look for stellar talent, this farm boy's definitely going places.
You might think that with a name like Mad Dog, he's got rabies or something, but that's actually not it. Mad Dog explains that he got his nickname because when he was a toddler, he had a thing for biting people (52.1). And despite his vicious-sounding name, he's actually a pretty gentle guy.
When Billie Jo makes her return to piano playing at one of Arley's school shows, Mad Dog seems to be the only person who still treats her the same as he did before the accident—he doesn't pity her or stare at her hands, but is genuine and friendly (51.4). He has every reason to be an arrogant jerk, but he isn't, not even when surrounded by female admirers.
Ultimately, Mad Dog becomes yet another one of Billie Jo's friends who leaves the Dust Bowl to find better opportunities, going to Amarillo to try to break into the music business on the radio. He says he "loves this land, no matter what" (86.6), but given everything these people have been dealing with and the amount of potential he has, we can't really blame him for leaving.
Billie Jo clearly has feelings for him though, and while she supports him going to live the dream, it heightens her own sense of being stuck that she struggles with throughout the story.