Governor Keith is one of the "worst" characters in the book, but even he can't keep Franklin down for long. When he first appears in the text, Keith seems like an awesome mentor. He encourages Franklin, who's just getting started in the business, and he offers to help him get started on his own, writing a letter to Franklin's father on his behalf. Since Franklin's family has been less than supportive of him up to this point – his father pulling him out of school and sticking him in his brother's business, Franklin having to leave the city altogether to find work again – Keith almost appears like a better kind of father figure. Even if he's just acting like a big brother, at first he fools Franklin and us into thinking that he's an improvement. Franklin's happy to go to England based on his advice; he thinks he's lucky to have found such an impressive benefactor so early in his career.
Unfortunately, Keith talks the talk but doesn't walk the walk. Franklin finds out later that Keith doesn't keep his word when he says anything to anyone. He's completely untrustworthy. Instead of being flattered, he should've been wary. Keith makes a habit of declaring promises he can't keep and never paying what he says he would. We wouldn't want to wait on him in a restaurant, that's for sure – forget tipping, he probably wouldn't pay the bill at all. He gets his in the end, though: when Franklin returns from England, he learns that Keith's been replaced as governor, and that's about the last we hear of him.