Who plays Frank in Hawaii Five-O?

Frank is played by Douglas Mossman.

How is Frank connected to other characters?

Frank has 7 mapped relationships in Hawaii Five-O. Explore the interactive relationship map for details.

Frank — Background Witness — Frank (Douglas Mossman)
Frank occupies a peripheral observational role, grounding the setting without influencing case outcomes or character dynamics.
Frank — Operational Base — Ben (Al Harrington)
Ben utilizes Frank's establishment as an operational base or information source.
Frank — Impostor Tracking — Ben (Al Harrington)
Frank cooperates with Ben to expose fraudulent operations.
Frank — Forensic Contact — Doc (Al Eben)
Frank and Doc share brief professional interactions during forensic procedures.
Frank — Jurisdictional Oversight — Governor (Richard Denning)
The Governor's office oversees Frank's activities during high-profile investigations.
Frank — Case File Exchange — Doc (Al Eben)
Doc provides medical reports that may relate to Frank's case files.
Frank — Administrative Intersection — Governor (Richard Denning)
Frank's appearances occasionally align with the Governor's administrative duties.