40.4% and 23.0% were both No. 1 in their year — 22 years of Korean ratings through one actor

People say that following one actor's filmography in order is a way to survey a country's television. So Ji-sub is an unusually good case. He carried a finale in the 40% range in 2004, and in 2026 he starred in the year's highest-rated drama.

But those two numbers are 40.4% and 23.0%. Twenty-two years apart, the achievement is the same and the number has almost halved. What this list actually documents is not a range of genres. It is the 22 years in which Korea changed how it counts a drama.

At a glance

The cells worth staring at are not the filled ones but the two empty ones. One Sunny Day and Mercy for None have no rating at all. They are empty for different reasons, and that difference explains the 22 years.

Nobody knows which title on this list the most people watched

A television rating measures what the sets in a panel of sample households were tuned to. Netflix does not appear in that survey; it publishes its own "views" and a count of countries where a title entered the top 10. The two figures use different units and do not convert into each other.

Put two incomparable numbers side by side and the bigger one reads like the winner.

Mercy for None took second place on Netflix's global non-English top 10 with 4.9 million views in its first three days, then went to first with 7.6 million in week two. It entered the top 10 in 75 countries and reached No. 1 in nine. Whether that gathered more people than the 7–8% average of Oh My Venus is not a question anyone can calculate.

So reading the table downwards as "he got less popular" is wrong. What shrank after 2004 was not this actor's audience but the share of people sitting in front of the same screen at the same moment.

The 40% of 2004 was possible because there were few channels

What Happened in Bali ran from 3 January to 7 March 2004 as an SBS weekend special, Saturday and Sunday at 9:45 pm, 20 episodes. It follows a poor travel agency worker in Bali (Ha Ji-won) caught between two men; So Ji-sub's Kang In-wook was not the lead, yet his quiet, unwavering devotion became the talking point. Jo In-sung co-starred.

That November he played Cha Mu-hyuk in KBS2's Monday–Tuesday drama I'm Sorry, I Love You. An orphan abused in his adoptive home and left to survive in the United States falls in love with Song Eun-chae (Im Soo-jung) while a bullet lodged in his head is killing him. Viewers reportedly campaigned to push the finale past 30%, and the role won him four categories at the KBS Drama Awards.

But one detail belongs here. The finale figure for What Happened in Bali is recorded as 40.4% in some sources and 36.2% in others. The I'm Sorry, I Love You finale is 29.2% by TNS and 27.0% by Nielsen. Even in 2004, the rating for a single broadcast varied by two to four percentage points depending on the firm doing the counting.

In 2004 the realistic channel choice for a national audience was far narrower than today, and binge-watching did not exist. A 40% produced under the condition that you had to watch at the same hour to follow the story is not the same measurement as a 23% in 2026, when more than ten platforms compete. How to read the rating number itself is set out separately in why 4.6% can be No. 1.

One title on this list never aired in Korea at all

One Sunny Day is a ten-part web drama released between 19 December 2014 and 10 January 2015. Kim Ji-ho (So Ji-sub), nursing a breakup, goes to Jeju Island for work and keeps running into a woman with the same given name (Kim Ji-won). It was shot in early winter on Jeju.

Yet it was released on LINE TV, for Thai viewers. It did not air in Korea. It later reached other regions through DramaFever.

A Korean actor's "essential works" list containing a title that never aired in Korea, made for a Southeast Asian market, is not just an odd credit. It means that by 2014 a Korean production had already tried skipping the domestic broadcast and treating Southeast Asian viewers as the primary audience. That is the previous generation of what Netflix does now.

With no broadcast, there is no rating.

There is effectively no public figure describing how this title performed.

Agent Kim Reactivated is the first title here to receive both numbers

Agent Kim Reactivated aired as an SBS Friday–Saturday drama from 26 June to 25 July 2026, ten episodes plus two specials, adapted from the Naver webtoon of the same name. An ordinary breadwinner is forced to expose the identity he had buried in order to save his daughter.

The finale drew 23.0% nationwide, 23.4% in the capital region, and a peak minute of 27.1%. It was No. 1 in its slot across all channels for ten consecutive episodes and set the highest rating of any 2026 miniseries. At the same time it spent three straight weeks at No. 1 on Netflix globally and entered the top 10 in 73 countries.

This is the first title in the filmography to hold a terrestrial rating and a global streaming rank at once. In 2004 only the first number existed; for Mercy for None in 2025, only the second.

A year earlier, Nam Gi-jun in Mercy for None is a former gang member who gave up his Achilles tendon protecting his brother and returns to the underworld eleven years later when that brother is murdered. It is webtoon-based, seven episodes, and dropped all at once rather than being scheduled weekly. When the episode count and the release pattern change, "finale rating" stops being a meaningful idea.

It is also no accident that the two most recent titles here are both webtoon adaptations. How long that path takes, and what changes along the way, is set out in how a webtoon becomes a drama. The habit of shifting the schedule around a final episode is covered in Korean drama finale scheduling.

What this means where you are

Using one actor as your spine still works. When you do it with this list, though, order it by year rather than by rating. That is the only order in which the movement shows — from a 2004 terrestrial weekend serial, through a 2014 web drama made for Southeast Asia, to a 2025 Netflix seven-parter.

That matters most to viewers in Southeast Asia. The fact that one title here reached Thailand before it reached Korea means Korean drama began treating the region as a first market, rather than an export destination, earlier than the usual story suggests.

Which channels and platforms make Korean dramas today is mapped in the channel landscape, and why episode counts keep shrinking is in why "16 episodes" is already statistically wrong.

So what will the next title's performance be written in? If Agent Kim Reactivated is the first to receive both numbers, the next question is which of the two disappears first.

Read next

• 4.6% and it was No. 1? — the background you need to read the table above properly
• How a webtoon becomes a tvN drama — the two most recent titles here are both adaptations
• Pulling the finale five minutes earlier and running it longer — the scheduling that builds a finale rating
• KBS, tvN, ENA, and the OTTs — where Korean dramas are made now
• "16 episodes" is already statistically wrong — how episode counts shrank

Sources

• Ten Asia — Agent Kim Reactivated finale records 23.0%
• Star News — Agent Kim Reactivated ends amid a syndrome; So Ji-sub tipped for the SBS acting awards
• Digital Daily — Mercy for None hits No. 1 on the Netflix global top 10 in week two
• Wikipedia (Korean) — What Happened in Bali
• Wikipedia (Korean) — Oh My Venus
• Jeonbuk Ilbo — I'm Sorry, I Love You ends at 29.2%