I've written about him before (as a live performer and about his documentary, Runnin' With Our Eyes Closed, which I still can't recommend enough).
I suspect that a lot of people heard him for the first time last night at the DNC. And that a lot of people who loved his SOUND were kinda shocked to discover his politics/worldview.
That's OK.
I've loved his songwriting since I first caught him live with Drive-By Truckers, years ago.
Here he explains the story behind where last night's song (his best IMO), "Something More Than Free," came from.
Any of his work is worth exploring further but you could do a lot worse than start here.