In Reginald Rose's awesome play Twelve Angry Men the character of "Juror No. Eight" corresponds to an amiable, analytical, and intelligent man who is actually the only one who gives the accused the benefit of the doubt. He demonstrates the actual need for true justice by considering a person innocent until proved guilty. Moreover, he is the first juror to show humanity throughout the play.
The stage synopsis describes the character of Juror 8:
He is a quiet, thoughtful gentleman who sees all sides of every question and constantly seeks the truth. He is a man of strength, tempered with compassion. Above all, he is a man who wants justice to be done, and will fight to see that it is.
This being mentioned, the play by Reginald Rose does not directly appoint a specific background, at least not for Juror Number Eight. This is because this character is meant to act upon the mandates of his conscience and his idiosyncratic respect for human life as opposed to the rest of the jurors, whose votes are a direct consequence of their immediate backgrounds. This is significant indeed, because it sets Juror Number Eight aside from the rest in that he is the only one that uses his brain and common sense, and not his schema, to emit a vote.
The evidence of this lays in that every other juror's background is defined in the play. For example: Juror Number Seven is a brash salesman, Juror Number Eleven is a refugee from Europe who has suffered injustice, and then Juror Number Twelve works in advertisement and is a snob.
Similarly, Rose points out how Juror Number Nine is a defeated man awaiting his death while Juror Number Ten is a passive-aggressive type man who just enjoys aggravating people. As for the rest, Jurors Five and Six are described as not very bright men, while Juror Number Four is a rich man of flashy disposition. The Foreman and Juror Two are weak and feeble men whereas Juror Number Three is the one who Eight calls a "sadist" because of his forceful ways and his brash behavior. Therefore, Juror Number Eight, with the description given above, calls for a man of deep character and enormous depth of thought and humanity.
This depth of character and humanity should be the result of the character's direct background. Although the play does not indicate the specific vocation of Juror No. Eight, the classical and truest-to-script film adaptation of the play (1957) adds more specific information that is actually allegorical. In this alternative adaptation of the play, Juror No. Eight's profession is that of an architect. This is significant because it would explain why Juror No. Eight is so analytical, organized and compartmentalized in his thinking. The film alternate version also points that this juror is actually a father of three which also would help explain why Eight, out of all the jurors, seems to have the most compassion for a nineteen year old defendant.
However, the fact that the film version, which is also a classic, adds information about Juror Eight does not take away from the validity of the play's description. If anything it helps to connect the missing dots that we may find in the script.