Gerry "Fitz" Fitzgerald is an insulting, nosy, loathsome individual who is drunken excuse for a husband, a lousy father, and a gambling washout but he has one saving grace - he is a brilliant psychologist with an uncanny ability to see the evil in people, bring them to confess and walk away unscathed. He seems to understand the criminal mind, most probably because his mind isn't that far removed from the criminals he deals with.
Cracker was based upon the Crackerseries for the UK that starred Robbie Coltrane.