 He prosecuted all types of cases under the watchful eye of his supervisor, Chief Deputy District Attorney H. M. "Staff" Stafford (Harry Morgan, who directed at least one episode himself).His opponent was usually Public Defender Katherine Benson (Julie Cobb).During the courtroom segments Ryan also provided a voice-over narration (like "Dragnet"), which brought the audience in on legal jargon and court procedures and allowed there to be less exposition in the dialogue, which was necessary due to the program's brevity, as most legal dramas have episodes twice the length of that of "The D.A.