Is Mr. Underwood a good citizen, or a bad citizen?

He's considered to be both. Though Mr. Underwood does bad things, he's still considered to be a good citizen. Atticus said something that made Mr. Underwood angry and he attempts to hurt Atticus the way Atticus hurts Mr. Underwood.

Take a look at the link I've provided below,

http://www.gradesaver.com/to-kill-a-mockingbird/study-guide/major-themes/