In the 15th century, despite so many accomplishments he has made for the people, King Sejong, his biggest goal is still remaining; the invention of original letters that can be read and written by all the people. But courtiers who want to dominate the knowledge and the power, are against his will and discourage his belief. Frustrated King Sejong hears about a bonze Sinmi a phonogram expert, and secretly brings him in the palace.
Unfortunately the movie The King's Letters is not yet available on HBO Max.
| Crew | Shin Young-hoon | Martial Arts Choreographer |
| Camera | No Ju-han | Still Photographer |
| Art | Yoon Sung-hye | Art Direction |
| Art | Choi Ji-hye | Art Direction |
| Art | Jang Hee-sun | Art Designer |
| Lighting | Hong Seung-chul | Lighting Director |
| Sound | Lim Hyung-geun | Production Sound Mixer |
| Sound | Yang Hye-jin | Sound Editor |
| Camera | Jeon Young-wook | Still Photographer |
| Camera | Ji Sung-yong | Key Grip |
| Directing | Cho Chul-hyun | Director |
| Writing | Lee Song-won | Writer |
| Writing | Geum Jung-yeon | Writer |
| Editing | Kim Sang-bum | Editor |
| Sound | Dalpalan | Original Music Composer |
| Camera | Kim Tae-kyeong | Director of Photography |
| Art | Ryu Seong-hie | Production Design |
| Costume & Make-Up | Kim Seo-young | Makeup & Hair |
| Costume & Make-Up | Shim Hyun-seob | Costume Design |
| Sound | Choi Tae-young | Sound Supervisor |
| Production | Seong Chang-yeon | Producer |
| Production | O Seung-hyeon | Executive Producer |
| Writing | Cho Chul-hyun | Writer |
| Costume & Make-Up | Lee Ji-yeon | Costume Design |
| Production | Kim Ji-hoon | Line Producer |
| Costume & Make-Up | Seo Eun-kyung | Costume Design |
| Camera | Lim Won-geun | Camera Operator |
| Directing | Kim Jun-su | Assistant Director |
| Editing | Park Jin-young | Digital Intermediate |
| Art | Yoon Hye-jung | Props |
