I don't know JD personally, so I really can't make a claim that he's a humble person, from personal experience.
At the same time, I have heard him talk (loads of YT videos out there, talk show segments, etc.) about the charities he's aligned with, how some of the charitable events are held, his role in all of that, and what it all means to him. As it pertains to these charities, the people involved and his own involvement, he doesn't like being the center of attention, or having his own name front and center. That's the actual definition of humility, to have a low estimate of one's own importance.
So I would say, as it relates directly to his charitable involvement, he does come across as very humble.
jmo