Beah Richards, playing the mother of the character played by Davis Roberts, is actually almost three years younger than Roberts.
This episode and its predecessor, Part 1, are two of the only episodes in the series filmed at least in part, and set, in California where McGarrett's sister is supposed to live. (The establishing shot of the courthouse, for example, was of the branch court located in the Los Angeles suburb of Van Nuys.) Accordingly, the credits uncharacteristically do not say, "Filmed entirely on location in Hawaii."
This episode features four actors who all appeared in the original series of Star Trek: Joanne Linville played the Romulan Commander in The Enterprise Incident, Bill Zuckert played Johnny Behan in Spectre of the Gun, Davis Roberts played Dr. Ozaba in The Empath and William Schallert who played Nilz Baris in The Trouble with Tribbles.
Director Abner Biberman worked with David Sheiner three years previous to this episode in the second series Voyage to the Bottom of the Sea episode "The Death Ship".