Jack Lord as Det. Steve McGarrett
James MacArthur as Det. Dan "Danno" Williams [ 1-11 ]
Kam Fong as Det. Chin Ho Kelly [ 1-10 ]
Zulu as Det. Kono Kalakaua [ 1-4 ]
Al Harrington as Det. Ben Kokua [ 5-6 ]
Herman Wedemeyer as Edward D. "Duke" Lukela [ 5-12 ]
Al Eben as Doc Bergman [ 3-9 ]
Peggy Ryan as Jenny Sherman [ 2-10 ]
William Smith as James "Kimo" Carew [ 12 ]
Sharon Farrell as Lori Wilson [ 12 ]
Moe Keale as Truck Kealoha [ 12 ]
Douglas Mossman as Det. Frank Kemana [ 12 ]
Khigh Dhiegh as Wo Fat
Richard Denning as Gov. Paul Jameson
Harry Endo as Che Fong
Glenn Cannon as D.A. John Manicote
Maggi Parker as May [ 1 ]
Morgan White as Att. Gen. Walter Stewart [ 1 ]
Laura Sode as Luana [ 11-12 ]