Introduced to the reader in Chapter 15, Mr. Underwood is a man unto himself. Scout describes him as self-important and the hub of the community as the head of the Tribune:
Mr. Underwood had no use for any organization but The Maycomb Tribune, of which he was the sole owner, editor, and printer.....He rarely gathered news; people brought it to him.....
Uncharacteristically, then, Mr. Underwood undertakes the initiative to cover the activities of Atticus from his office window, which overlooks the jail, on the night that the mob comes for Tom Robinson. After Mr. Cunningham and the others leave, Scout notices the engrossed conversation between Underwood and Atticus:
...it seemed that Atticus and Mr. Underwood would talk for the rest of the night....
From this conversation with Atticus and from his own witnessing of the trial, Mr. Underwood apparently is greatly moved by the injustice done to Tom Robinson. This apparent change in Mr. Underwood involvement as evinced in his castigating editorial, an editorial which is also ironic as pointed out by Atticus's remark about the evening at the jail: "You know, it's a funny thing about Braxton [Underwood]. He despises Negroes, won't have one near him."
Because of his reputation for racial prejudice, Mr. Underwood's critical words about Tom's trial have an impact upon the readers of The Maycomb Tribune who all know how he has always felt about Negroes. But, now, he writes a scathing invective against those who have condemned a cripple, likening it to those who kill songbirds, alluding to the title. Mr. Underwood perceives that Tom Robinson is a sacrificial victim of the social climate of Maycomb, Alabama, in the 1930s. This perception of Mr. Underwood underscores the mockingbird theme as well as suggesting that some change may come to racial attitudes in Maycomb.