You know that feeling when you've been friends with someone so long that the idea of dating them feels both like the most natural thing in the world and a total recipe for disaster? That’s basically the entire energy of Soundtrack #1. It’s a short, four-episode "music drama" that hit Disney+ back in 2022, but people are still talking about the cast of Soundtrack #1 because, honestly, the chemistry was just different.
Most K-dramas drag things out over sixteen hours. This one? It’s a sprint.
Because it’s so short, the weight of the entire show rests on the shoulders of two people. If the leads didn't click, the whole thing would have been a boring slog through tired tropes. Instead, we got Han So-hee and Park Hyung-sik. It’s a pairing that, on paper, sounds like a visual explosion, but on screen, it felt surprisingly grounded.
The Core Duo: Han So-hee and Park Hyung-sik
When we talk about the cast of Soundtrack #1, we are really talking about Han Seon-woo and Lee Eun-soo.
Park Hyung-sik plays Han Seon-woo. He’s a photographer. He’s the kind of guy who has been hopelessly in love with his best friend for nineteen years but would rather eat glass than tell her and risk losing her. Hyung-sik is a veteran at this point—you might know him from Strong Girl Bong-soon or Happiness. He has this specific way of looking at a co-star that makes you believe he’s actually pining. It’s all in the eyes. In this role, he’s quiet, observant, and deeply "coded" as the reliable best friend.
Then you have Han So-hee as Lee Eun-soo. This was a massive 180 from her previous roles. If you saw her in The World of the Married or the gritty revenge thriller My Name, seeing her as a bubbly, slightly chaotic lyricist is a shock. She’s honest. Sometimes too honest. She’s struggling to write lyrics about unrequited love because she’s never actually felt it—or so she thinks.
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The plot kicks off because she’s failing at her job. She asks Seon-woo to move in for two weeks to help her understand what "one-sided love" feels like.
Classic mistake.
The Supporting Players and Surprise Cameos
While the show is hyper-focused on the main two, the supporting cast of Soundtrack #1 helps flesh out the world so it doesn't feel like they're living in a vacuum.
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- Kim Joo-hun appears as Kang Woo-il. He’s the resident "other guy"—a successful composer who shows interest in Eun-soo. You’ve definitely seen him before; he was the publisher in It's Okay to Not Be Okay and the mayor in Big Mouth. Here, he’s charming and professional, providing just enough friction to make Seon-woo sweat.
- Lee Jung-eun plays Eun-soo’s mother. She’s a powerhouse actress (yes, the housekeeper from Parasite). Even in a tiny role, she brings that "mom energy" that makes the characters' lives feel lived-in.
- Yoon Byung-hee plays Dong-hyeon, Seon-woo’s colleague. He’s mostly there for the "bro" vibes and to give Seon-woo someone to talk to other than Eun-soo.
And then there’s the cameo. Seo In-guk pops up as Jay Jun, a famous singer. It’s a blink-and-you-miss-it moment in the later episodes, but for K-drama fans, it was a fun "Easter egg" that added a bit of star power to the musical theme.
Why the Casting Choice Changed the Vibe
A lot of people expected Soundtrack #1 to be another flashy, high-budget romance. But the director, Kim Hee-won (who also did Vincenzo and Little Women), went for something more atmospheric.
The chemistry isn't about big, sweeping declarations. It’s about the way they share a cup of makgeolli or how Seon-woo fixes Eun-soo’s scarf. Han So-hee played Eun-soo with a lot of "bruh-girl" energy—she’s messy, she drinks, she’s loud. It made the transition to romance feel more earned because they actually felt like friends who had seen each other at their worst.
There was a bit of a divide in the reviews. Some fans felt the four episodes weren't enough to really "feel" the twenty-year history. Others loved the brevity. Honestly? In a world of bloated 90-minute episodes, a four-part series that you can finish in a single rainy afternoon is kind of a gift.
Beyond the Main Cast: The "Music" as a Character
Since it’s called Soundtrack #1, the music is arguably a cast member itself. Unlike most dramas that release an OST as the show airs, this one released the songs before the show started.
Artists like Kyuhyun, Davichi, and Lee Hi lent their voices to the project. The lyrics Eun-soo is trying to write in the show are actually the songs you're hearing. It’s a meta-narrative that works because the cast of Soundtrack #1—specifically Han So-hee—has to act out the process of creating those feelings.
Quick Cast Breakdown
| Actor | Character | Role/Vibe |
|---|---|---|
| Park Hyung-sik | Han Seon-woo | The pining photographer. Extremely "soft boy" energy. |
| Han So-hee | Lee Eun-soo | The struggling lyricist. Chaos personified but very loyal. |
| Kim Joo-hun | Kang Woo-il | The professional rival. The "could-have-been" love interest. |
| Lee Jung-eun | Eun-soo's Mom | The voice of reason (and tarot card enthusiast). |
| Seo In-guk | Jay Jun | The celebrity cameo that made everyone scream. |
What Happened to Soundtrack #2?
If you're looking for the same cast of Soundtrack #1 in the sequel, you’re going to be disappointed. Soundtrack #2 was released in 2023, but it’s an anthology. It features an entirely different story with Geum Sae-rok and Steve Noh.
It’s good, sure. But it doesn't quite have that "lightning in a bottle" feeling of the first one. There’s something about the specific visual pairing of Han So-hee and Park Hyung-sik that fans still post about on TikTok and Twitter (X) years later.
Actionable Takeaways for Your Watchlist
If you haven't seen it yet, or you're planning a rewatch, here is how to get the most out of it:
- Watch it in one go. It’s basically a two-and-a-half-hour movie. Splitting it up ruins the "slow burn" pacing.
- Pay attention to the photography. The shots Seon-woo takes of Eun-soo throughout the episodes actually tell the story of his feelings better than the dialogue does.
- Listen to the lyrics. Since the FL is a lyricist, the songs aren't just background noise; they are the literal plot.
- Check out Han So-hee’s other 2022/2023 work like Gyeongseong Creature to see just how much she changed her acting style for this specific role.
The cast of Soundtrack #1 might be small, but they managed to turn a very simple "friends-to-lovers" trope into something that felt surprisingly intimate. It’s not a masterpiece of complex plotting, but as a cozy, winter-vibes romance? It’s pretty much perfect.