Sejun
A diminutive of Korean masculine names containing the hanja character "se" meaning truth or victory.
Name Census estimates that about 6 living Americans carry the first name Sejun. The name is used almost exclusively for boys. The average person named Sejun today is around 5 years old, and the year with the single highest number of Sejun births was 2021 (6 babies).
This page is the full Name Census profile for Sejun. Below you will find a gender breakdown showing how the name splits between male and female registrations, a year-by-year popularity chart stretching back to 1880, decade-level totals, the top US states for this name, its meaning and etymology, and a set of frequently asked questions with data-backed answers.
For a British comparison, Name Census UK has a UK baby-name profile for Sejun with official rankings and popularity over time.
Key insights
- • Fewer than 100 living Americans are believed to carry the name Sejun. It is among the rarest names in the SSA records.
People living today
6
~ 1 in 57,125,723 Americans
Peak year
2021
6 babies that year
Average age
5
years old
2021 SSA rank
#11,896
Tracked since 2021
Popularity
Sejun: popularity over time
Babies born per year
Decades
Sejun by decade
The table below breaks the full SSA timeline into ten-year windows. Each row shows how many male and female babies were given the name Sejun during that decade, along with a combined total. This is useful for spotting eras where the name surged or retreated.
| Decade | Male | Female | Total |
|---|---|---|---|
| 2020s | 6 | 0 | 6 |
Origin
Meaning and history of Sejun
Sejun is a Korean given name that has its origins in the ancient Korean language. The name can be traced back to the Silla Kingdom, which ruled over parts of the Korean peninsula from 57 BC to 935 AD.
The name Sejun is composed of two Korean words: "se", meaning "world" or "universe", and "jun", meaning "noble" or "gentle". Therefore, the name Sejun can be interpreted as "noble one of the universe" or "gentle world".
One of the earliest recorded instances of the name Sejun can be found in the Samguk Sagi, a historical record of the Three Kingdoms of Korea written in 1145 AD. The text mentions a noble scholar named Sejun Kim, who lived during the Silla Kingdom in the 8th century AD.
Throughout Korean history, several notable figures have borne the name Sejun. One such individual was Sejun Park (1629-1703), a renowned Confucian scholar and writer during the Joseon Dynasty. His works, which include commentaries on classical texts, had a significant influence on the intellectual landscape of his time.
Another historical figure named Sejun was Sejun Yi (1745-1821), a prominent calligrapher and artist during the late Joseon Dynasty. His calligraphic works are celebrated for their elegance and mastery of the brushstroke.
In the 19th century, Sejun Choi (1834-1901) was a respected statesman and diplomat who played a crucial role in Korea's relations with neighboring countries, particularly during the era of modernization and opening to the West.
A more recent historical figure with the name Sejun was Sejun Kim (1905-1984), a pioneering film director and screenwriter who is considered one of the founders of Korean cinema. His films, such as "Broken Strings" (1936) and "Hurrah! For Freedom" (1946), explored themes of social justice and national identity.
While the name Sejun has roots in ancient Korean history, it has continued to be used as a given name in modern times, reflecting the enduring cultural significance and appreciation for its meaning and heritage.
People
Sejun + last name combinations
How many people share a full name with Sejun as the first name? Click a combination below to see the estimate, or search any pairing.
Related
Other names starting with S
Other first names starting with S with a similar number of bearers.
FAQ
Sejun: questions and answers
How many people in the U.S. are named Sejun?
Name Census puts the figure at roughly 6 living Americans. We arrive at this by taking every SSA birth registration for Sejun going back to 1880 and adjusting each cohort for expected survival using CDC actuarial life tables. The result is an age-weighted living-bearer count, not a raw birth total. That works out to about 1 in 57,125,723 US residents.
Is Sejun a common name?
We classify Sejun as "Very Rare". It ranks above 22.3% of all first names in the SSA dataset by living bearers. Across the full history of the data, 6 babies have been registered with this name.
When was Sejun most popular?
The single biggest year for Sejun was 2021, when 6 babies received the name. The fact that the average living Sejun is about 5 years old gives you a rough sense of which era contributed the most bearers who are still alive today.
What does the SSA popularity chart show?
The chart tracks births, not the number of people alive with the name today. Each point shows how many babies were given the name Sejun in that year. That makes it useful for spotting when the name rose, peaked, or faded.
Is Sejun a male name?
Yes, 100.0% of people registered as Sejun in the SSA data are male. You can see the full per-sex comparison in the gender distribution section above, which includes the latest year rank, birth count, and peak year for each sex.
Is Sejun still being used today?
Yes. The SSA still recorded Sejun in 2024, and the page above shows its latest-year rank where available. A name can be well past its peak and still remain in steady use, especially if it built up a large population over earlier decades.
Why can a name have a lot of living bearers even if it is not trendy now?
Because living-bearer counts and current baby-name popularity measure different things. A name like Sejun can build up a very large population over many decades, even if fewer parents are choosing it now than they did at its peak.
Where does this data come from?
First-name figures come from the Social Security Administration's national baby name files, which cover every name on a birth certificate from 1880 to 2024. Living-bearer estimates layer in CDC actuarial life tables broken out by sex to account for mortality. The population baseline (342,754,338) is the Census Bureau's latest national estimate. You can read the full calculation on our methodology page.
Does every first name have Census demographic data?
No. The public Census first-name release only covers names that met the Bureau's publication rules, so many rarer names in the SSA files do not have a published Census demographic snapshot. In those cases, the page still shows the SSA trend, gender history, and state data.
How common is the name Sejun?
Our sister site HowManyOfMe.org answers how many people share the name Sejun at a glance, with the living-bearer count up front.