Uncle Buck is salt of the earth—a good, if a little nutty, old guy. He runs his mouth a lot, insulting people's family members and even his own twin brother (gosh, if his name is Amodeus, what'd they call the twin?). But he has serious values and is not going to compromise them, no matter the consequences.
He and his brother are famous for being easy on their slaves and taking care of poor people. They're also famous for winning and losing huge fortunes to each other in their nightly card games.
But what we really love about Uncle Buck, besides all his cute quirks, is that he takes care of Bayard and Ringo, helping them keep their cool and hunt down Grumby after Granny is murdered. He gets shot in the arm for his trouble, but barely complains about it because he's more interested in justice than his own comfort. What a guy!