Clarence Earl Gideon is the title character. Gideon is a complex figure. Though he is rarely actually present in the narrative, his influence looms over proceedings. It is his determination and sense of injustice that motivates the plot, driving the case relentlessly toward the Supreme Court. Once his name is fixed to legal documents, there is a sense that his force of personality disappears—the professionals take over the legal process and he has very little to do with it. As such, Gideon exists very much in abstract form. His situation is one that is discussed in dry, objective terms in the Court. Gideon takes on a role as the embodiment of the matter being debated, rather than a character in his own right.

Occasionally, however, Gideon is permitted to speak on his own terms. The best example of this is the autobiographical letter that he sends to Fortas. This is reprinted in the text, with the idiosyncratic spelling errors and grammatical mistakes left in place. This presents Gideon as something markedly different to the character that inhabits the legal abstract. On paper, he is a dangerous felon who robbed a pool hall.