You probably know Mark Harmon as the silver-haired, stoic Special Agent Leroy Jethro Gibbs. For nearly two decades, he was the face of NCIS, the guy who always had a rule for every situation and a basement boat that never seemed to get finished. But lately, people aren't just talking about his acting. They’re buzzing about Ghosts of Honolulu Mark Harmon, a project that pivots from his fictional naval investigations into the gritty, high-stakes reality of World War II counterintelligence.
It’s not a ghost story. Not in the supernatural sense, anyway.
The "ghosts" are the men who operated in the shadows of Oahu long before the first bombs fell on December 7, 1941. Specifically, this is about Douglas Wada and Takeo Yoshikawa. One was a Japanese-American working for the U.S. Navy; the other was a Japanese spy. Their paths crossed in a chess match of surveillance and deception that most history books completely ignore. Honestly, it's wild that this story stayed buried for so long. Harmon didn’t just stumble onto this; he co-authored a non-fiction book titled Ghosts of Honolulu: A Japanese Spy, a Japanese American Spy, and the Untold Story of Pearl Harbor with Leon Carroll Jr., a former NCIS special agent who served as a technical advisor on the show.
Why Mark Harmon is Obsessed With This Story
Harmon has always had a deep connection to the military and law enforcement, partly because of his father, Tom Harmon, a Heisman winner and a pilot in WWII. But the bridge to this specific piece of history was Leon Carroll Jr.
Carroll spent years in the real NCIS. While most actors just read their lines and go home, Harmon spent twenty years soaking up the culture of the agency. He learned that the Office of Naval Intelligence (ONI) was the predecessor to what we now know as NCIS. When he and Carroll started digging into the archives, they found Douglas Wada.
Wada was a trailblazer. As a Kibei (a Japanese-American born in the U.S. but educated in Japan), he faced immense suspicion from his own government. Yet, he became the first Japanese-American to work as an undercover agent for the ONI. He was basically a real-life Gibbs before Gibbs existed, navigating a world where his heritage made him an asset to the Navy but a target for racial prejudice. Harmon seems drawn to that duality. It’s a story about loyalty when the country you love doesn't entirely trust you back.
The Spy Who Lived Next Door
The other half of the Ghosts of Honolulu Mark Harmon narrative focuses on Takeo Yoshikawa. If you’ve ever watched a spy thriller, Yoshikawa is the guy you’d cast as the lead. He arrived in Honolulu in early 1941 under the alias "Tadashi Morimura," posing as a junior diplomat.
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He didn't use high-tech gadgets. He used his eyes.
Yoshikawa would spend his days wandering around Pearl Harbor. He'd take taxi rides. He'd rent small planes for "sightseeing" tours. He’d sit on the hills overlooking the Pacific Fleet, sketching the positions of the battleships. He even frequented a Japanese tea house called Shunchō-rō, which had a perfect view of the harbor. He was a "ghost" because he was hiding in plain sight. While the Americans were looking for a massive, coordinated conspiracy, Yoshikawa was just one guy with a very good memory and a notepad.
Harmon’s book highlights the massive failure of imagination on the American side. We assume intelligence is always about intercepted telegrams or code-breaking—and that played a role—but the human element, the humint as they call it, was where the real battle was fought.
Douglas Wada: The Hero Nobody Knew
It’s easy to focus on the tragedy of Pearl Harbor, but the work Douglas Wada did was instrumental in the aftermath. He wasn't just translating documents. He was interrogating prisoners. He was trying to figure out how the Japanese Navy operated from the inside out.
Working with Carroll, Harmon brings a unique perspective to Wada’s life. Because Carroll was an actual NCIS agent, they don't just look at the dates and facts. They look at the tradecraft. How do you flip a source? How do you maintain a cover in a small community like Honolulu where everyone knows everyone?
Wada’s story is also a heavy reminder of the Executive Order 9066 and the internment of Japanese Americans. Imagine serving your country in total secrecy while people who look like you are being rounded up and sent to camps. That’s the emotional core of what Ghosts of Honolulu Mark Harmon explores. It’s a messy, complicated piece of American history that isn't wrapped up in a neat little bow.
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The Reality of Pre-War Honolulu
Honolulu in 1941 wasn't just a tropical paradise. It was a pressure cooker. You had a massive military presence, a huge immigrant population, and a shifting global landscape.
- The FBI was at odds with the ONI.
- The Army and Navy weren't talking to each other.
- The local police were caught in the middle.
This lack of communication is a recurring theme in the book. Harmon and Carroll illustrate how the "silos" of information allowed Yoshikawa to operate for months without being apprehended. It’s a classic intelligence failure. The clues were there. The "ghosts" were moving right in front of them, but nobody was looking at the whole picture.
Is There a TV Show Coming?
Since the book was released, everyone wants to know if Mark Harmon is going to bring this to the screen.
There hasn't been a formal announcement of a "Ghosts of Honolulu" scripted series yet, but the rumors are persistent. Given Harmon’s production company, Wings Productions, and his long-standing relationship with CBS, it seems like a no-brainer. The book reads like a treatment for a limited series. It has the tension of The Americans but with the historical weight of Band of Brothers.
Even if a show doesn't materialize immediately, the book itself serves as a foundational text for a new "NCIS Origins" type of storytelling. It moves away from the procedural "body of the week" format and into the realm of historical espionage.
Why This History Matters in 2026
We live in an era of digital surveillance and cyber warfare. The idea of a spy sitting on a hill with a pair of binoculars feels quaint. But the human psychology hasn't changed.
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The Ghosts of Honolulu Mark Harmon project reminds us that the biggest threats often come from the things we choose to ignore. The "ghosts" are the people we don't see because we’ve already decided they aren't important. Whether it's the Japanese-American agent whose loyalty is questioned or the "diplomat" who spends too much time looking at ships, these figures shaped the course of the 20th century.
Harmon’s transition from actor to historian-of-sorts is actually quite fitting. After years of playing a character who values the "silent types," he’s finally giving those real-world silent types a voice.
How to Explore the History Yourself
If this specific niche of WWII history fascinates you, don't just stop at the book.
- Research the Niihau Incident: This was a weird, terrifying event right after the Pearl Harbor attack involving a downed Japanese pilot and local residents. It heavily influenced how the U.S. viewed Japanese-Americans and is a crucial backdrop to Wada’s era.
- Visit the USS Bowfin Submarine Museum: If you ever find yourself in Hawaii, this museum (located right next to the Pearl Harbor National Memorial) does a great job of explaining the underwater and intelligence side of the war.
- Read Leon Carroll Jr.’s background: Understanding the "NCIS" connection helps you see why the book focuses so much on evidence and interrogation techniques rather than just "war stories."
- Check out the ONI Archives: Much of the declassified material regarding Douglas Wada is now accessible through the National Archives.
The story of the Ghosts of Honolulu Mark Harmon is a rare case where the truth is actually more interesting than the fiction we see on TV. It’s about the guys who didn't get the medals or the parades because their work was, by definition, supposed to stay in the dark.
By pulling these stories into the light, Harmon and Carroll have done more than just write a bestseller; they've corrected a massive oversight in our collective memory of the "Day of Infamy." It turns out the most important battles weren't just fought with planes and ships, but with a few quiet conversations in a tea house and the unwavering resolve of a man who had to prove his loyalty every single day.
To dig deeper into the actual documents that inspired the book, look up the "Wada Files" at the National Archives or explore the oral histories of the 442nd Regimental Combat Team, which often overlap with the themes of Japanese-American service during this period. Understanding the cultural friction of 1940s Hawaii provides the necessary context for why these intelligence operations were so fraught with danger and ethical complexity.