When Moon Lovers: Scarlet Heart Ryeo premiered on SBS, it didn't just capture ratings; it sparked an international phenomenon that fans still discuss passionately years later. At the heart of this sweeping historical romance was an ensemble cast that balanced rising young talent with seasoned veterans. Let's look past the traditional summaries and examine the actual ensemble that brought the Goryeo dynasty to life.
Finding a production with this much star power in a single call sheet is rare. The series relied heavily on its actors' chemistry to navigate complex political intrigue, tragic romance, and intense sibling rivalry.
The Core Leads: IU and Lee Joon-gi
Every great historical drama needs anchors, and Scarlet Heart Ryeo built its entire emotional framework around its two central leads.
Go Ha-jin and Hae Soo (Played by IU)
Lee Ji-eun, known globally as IU, took on the grueling dual role of Go Ha-jin, a modern cosmetics makeup artist transported back in time, and Hae Soo, a noblewoman trapped in the royal court. IU brought a distinct vulnerability to the screen that kept viewers grounded as the political stakes escalated. Her performance shifted from bewildered modern outsider to resilient court lady, anchoring the narrative chaos. IU was already a massive music star when she took this role, but her work here proved her acting range, leading to later critical acclaim in series like My Mister and Hotel del Luna.
Wang So, the 4th Prince (Played by Lee Joon-gi)
Lee Joon-gi played the fierce, scarred 4th Prince who would eventually become King Gwangjong. Wearing a mask that hid both a physical scar and deep emotional trauma, Lee carried the brooding anti-hero archetype with sharp intensity. His ability to convey fierce loyalty and absolute vulnerability through subtle micro-expressions defined the show's dramatic tension. By 2016, Lee was already a veteran of historical action dramas, having starred in The King and the Clown and Iljimae, and his stunt work and sword handling elevated every action sequence he appeared in.
The Royal Rivalry: The Supporting Princes
The Goryeo royal family provided a massive playground for young actors to showcase their talents, playing a collection of princes with wildly different temperaments, ambitions, and loyalties.
Wang Wook, the 8th Prince (Played by Kang Ha-neul)
Kang Ha-neul played the gentle, scholarly 8th Prince who slowly transformed under the crushing weight of ambition and family pressure. Kang played this gradual moral descent with chilling subtlety. Instead of turning into a cartoon villain overnight, his character made small, justifiable compromises that compounded into tragedy. Kang's career trajectory continued upward after this role, winning the prestigious Baeksang Arts Award for Best Actor for When the Camellia Blooms.
Wang Yo, the 3rd Prince (Played by Hong Jong-hyun)
Hong Jong-hyun stepped into the role of the primary antagonist, the ambitious and ruthless 3rd Prince. Hong gave the character a cold, calculating edge, creating a genuine physical and political threat to Wang So. As a model-turned-actor, Hong used his imposing physical presence to dominate scenes, proving his chops in a complex villainous turn that required a commanding screen presence without leaning into melodrama.
Wang Wook, the 13th Prince / Baek-ah (Played by Nam Joo-hyuk)
Nam Joo-hyuk played the artistic and freedom-loving 13th Prince, an ally to the main leads who found himself dragged into court politics despite his preferences. Nam's performance offered a gentle respite from the constant scheming of the older princes. His chemistry with Seohyun's character Woo-hee formed one of the most poignant secondary romances in the series. Nam later cemented his leading man status in dramas like Weightlifting Fairy Kim Bok-joo and Start-Up.
Wang Won, the 9th Prince (Played by Yoon Sun-woo)
Yoon Sun-woo portrayed the opportunistic and sycophantic 9th Prince, who allied himself with whatever faction promised the most power. Yoon played the character with a nervous energy, highlighting the desperation of a minor player trying to survive among heavyweights.
Wang Eun, the 10th Prince (Played by Baekhyun)
EXO member Baekhyun made his dramatic acting debut as the playful, mischievous 10th Prince. Baekhyun brought genuine comedic relief to the early episodes, portraying a character who was entirely unsuited for the brutal realities of palace life. His youthful energy provided a sharp contrast to the grim political environment, making his later storyline one of the most emotionally devastating arcs in the series.
Wang Jung, the 14th Prince (Played by Ji Soo)
Ji Soo played the youngest prince, fiercely loyal, athletic, and fiercely protective of Hae Soo. Ji brought a hot-headed youthfulness to the role, evolving from a bratty younger brother into a mature, dependable figure by the series' final episodes.
The Court and Supporting Ensemble
Beyond the royal brothers, several key figures shaped the narrative and the daily life within Songak.
Princess Yeon-hwa (Played by Kang Han-na)
Kang Han-na played the ambitious Princess Yeon-hwa, the 8th Prince's sister who viewed marriage and court alliances as chess pieces. Kang played her with sharp intellect and cool composure, refusing to let her character be reduced to a standard jealous rival. Her political maneuvering rivaled any of the male characters.
Woo-hee (Played by Seohyun)
Seohyun, member of the girl group Girls' Generation, portrayed Woo-hee, a gisaeng who hid a secret identity as a survivor of a conquered royal family seeking revenge. Seohyun trained extensively in traditional dance and sword fighting for the role, delivering a performance defined by tragic dignity.
Behind the Scenes and Direction
Director Kim Kyu-tae helmed the project, adapting it from the Chinese novel Bu Bu Jing Xin and its subsequent television adaptation Scarlet Heart. Kim is well-known for his visually striking directing style in dramas like It's Okay, That's Love and Our Blues. He utilized wide-angle landscape shots and intimate close-ups to contrast the massive scale of the Goryeo court with the lonely emotional states of the characters.
The production scale was massive for a Korean drama of its era. Unlike typical live-shoot Korean television productions that write episodes week-to-week based on viewer feedback, Scarlet Heart Ryeo completed 100 percent of its pre-production filming before airing its first episode on SBS. This gave the crew time to handle elaborate period costumes, massive set pieces, and complex historical battle choreography.
Common Misconceptions About the Cast and Production
Viewers often look back at the show with specific misunderstandings regarding its release and casting choices.
- It was not an instant ratings smash in South Korea: While the series became a massive viral hit across China, Southeast Asia, and North America via platforms like Viki, its domestic live television ratings on SBS faced stiff competition from other broadcasts during its initial run.
- The cast wasn't assembled overnight: Securing an ensemble this large required months of scheduling, especially given that many of the younger actors and idols were balancing concurrent music promotions, variety shows, and modeling contracts.
- Idol casting drew initial skepticism: When the lineup featuring IU, Baekhyun, and Seohyun was announced, Korean media outlets questioned whether pop idols could handle heavy historical dialogue. The cast's dedicated performances ultimately quieted those criticisms.
Frequently Asked Questions
Why hasn't Scarlet Heart Ryeo received a second season?
Despite massive international fan demand and cliffhangers that left viewers wanting resolution, production logistics, actor availability, and the specific conclusion of the original Chinese source material made a direct continuation impractical. The main cast moved on to other leading roles across different networks.
Was Scarlet Heart Ryeo a remake?
Yes. The series is a South Korean adaptation of the Chinese web novel Bu Bu Jing Xin by Tong Hua. While the Chinese adaptation set its story during the Qing dynasty, the Korean version relocated the narrative to the early Goryeo dynasty.
How old were the actors playing the princes?
During filming in late 2015 and early 2016, the main cast of princes consisted mostly of actors in their mid-to-late twenties, with some younger idols like Baekhyun being slightly younger. This aligned with the historical ages of King Taejo's actual sons during the early Goryeo succession struggles.
Where was the drama filmed?
The production utilized a mix of extensive indoor studio sets built specifically for the Goryeo period architecture and scenic outdoor locations across South Korea, including historic villages and natural parks designed to mimic medieval landscapes.
