I know someone who worked on his stage crew. He describe Kiellor as an arrogant boor, and he got even worse after his stay in NYC. A very nasty character, especially towards anyone he disagreed with in the slightest way. He had some sketches where he describes Minnesotans as having a junior high mentality. Quite accurate, and Keillor fits the description as well.
Keillor was also known to be a groper.
He sounds a little like another comedian from the Midwest, David Letterman.