Korea's unusual religious profile in East Asia
Christianity's presence in South Korea is genuinely unusual by regional standards. Japan's Christian population has remained under 1% of its total population for generations. China's is a low single-digit share. South Korea is a marked outlier: Statistics Korea's 2015 census found that roughly 19.7% of South Koreans identified as Protestant and roughly 7.9% as Roman Catholic, putting the combined Christian share of the population at around 27–28%, alongside about 15.5% identifying as Buddhist and a majority, just over 56%, reporting no religious affiliation. Survey figures have shifted somewhat since 2015 and different polling organizations report slightly different splits, so these numbers are best read as an order of magnitude — roughly a quarter to just under a third of South Koreans — rather than a fixed figure. Whatever the precise current number, the underlying fact is well established: South Korea has, by a wide margin, the largest Christian population of any East Asian country as a share of its people, and Seoul alone is home to some of the largest individual Protestant congregations in the world.
Catholicism reached Korea first, in the late eighteenth century, arriving not primarily through missionary contact but through Korean scholars encountering Jesuit theological writings brought back from Beijing; Korea's first Catholic prayer house was established in 1784 by a Korean convert, Yi Sung-hun, following his own baptism abroad. The faith spread initially among Confucian scholars drawn to its ideas about human equality, and it survived a brutal nineteenth-century persecution that killed thousands of Korean converts, including the country's first native-born priest, Andrew Kim Taegon, executed in 1846. Protestant missionaries arrived later, beginning with the Presbyterian medical missionary Horace Allen in 1884, followed by figures such as Henry Appenzeller, who focused heavily on medicine and education rather than direct evangelism, which was restricted under Korean law at the time. Those missionary-founded institutions include universities that remain prominent in South Korea today. A recurring explanation offered by historians for Christianity's comparatively rapid growth in Korea — relative to Japan and China — points to several reinforcing factors: mission schools taught literacy using Korea's own hangul alphabet rather than classical Chinese, which broadened access well beyond the traditional literate elite; Christian teaching on human dignity resonated as a challenge to a rigid Confucian social hierarchy; and, during the Japanese colonial period (1910–1945), Korean Christians' refusal to participate in mandatory Shinto shrine worship linked the faith with Korean national identity and resistance to colonial rule in a way that had no real parallel in Japan itself.
The practice of adopting an English given name
Separately from the religious history, Korean immigrants to English-speaking countries — the United States chief among them — have long practiced adopting an English given name, used alongside or instead of a Korean one in English-language contexts. The reasons commonly cited are practical rather than ideological: an anglicized form is straightforward for English speakers to pronounce, read, and remember, which matters in school, in the workplace, and in everyday transactions in a way that a Korean given name unfamiliar to most English speakers often does not. First-generation immigrants in particular have described the practice as functioning almost like a second, situational identity — used with English-speaking colleagues and acquaintances, set aside in Korean-speaking or family contexts where the original Korean form remains primary.
This is not unique to Korean immigrants; the broader practice of immigrants adopting a host-country identity has a long history across many immigrant groups arriving in the United States, and it long predates Korean immigration specifically. What distinguishes the Korean-American case is less the existence of the practice than the particular pool it draws from, given the community's religious composition — a pool weighted heavily toward biblical choices rather than toward secular English options generally.
Why the names skew biblical
Korean-American religious affiliation runs meaningfully higher than South Korea's own national rate. Surveys of Korean-Americans have found Christian affiliation in the range of roughly 60% to 71% depending on the survey and how affiliation is measured — substantially above the roughly quarter-to-third of the population that identifies as Christian in South Korea itself. Some of that gap reflects the specific history of Korean immigration to the United States: many of the earliest Korean immigrants, arriving from the early twentieth century onward, were themselves Christians who had connections to American missionary networks in Korea, and later waves of immigration, particularly after US immigration law changed in 1965, brought a population in which church membership functioned as an important source of community and mutual support in a new country — a role documented by researchers studying immigrant religious life more broadly.
Given that religious composition, it follows fairly directly that the pool of English given names Korean immigrant parents and immigrants themselves have drawn from over the decades skews toward biblical choices rather than an even sample of all English options. Onomastic and journalistic accounts of this practice describe a range of biblical choices appearing disproportionately often among Korean-American given names — for instance, "Grace" has been documented as an especially common choice among Korean-American women, frequently selected in part because it renders a Korean name element with a related meaning, or simply because it was recommended to a newly arrived child by a teacher or pastor as "common and easy to pronounce." "John" occupies a comparable position among men's given names, for reasons that reinforce rather than compete with the biblical pattern: it is not merely a biblical name in a general sense but one carried by two of the New Testament's most prominent figures, John the Baptist and the Apostle John, traditionally credited as an author of the Gospel of John. That dual religious prominence made "John" one of the single most heavily used given names across Christian Europe for centuries, well before any Korean-American naming pattern existed — meaning a Korean-American parent or immigrant choosing an easily recognized, unmistakably Christian English option had, in John, a choice that was already sitting near the top of the available pool for exactly that reason.
Generational patterns
The practice is not uniform across generations, and accounts from within the Korean-American community consistently describe it shifting. First-generation immigrants — those who arrived in the United States as adults — have often described adopting an English name as a practical accommodation made after arrival, layered on top of a Korean one that remains the primary marker of identity within family and Korean-speaking community life. For their US-born children and grandchildren, the pattern looks different: an English given name is frequently chosen at birth, sometimes as the sole one recorded on a birth certificate, sometimes alongside a Korean middle name, reflecting a family's expectation that the child will operate primarily in English-language institutions from the start rather than acquiring one later as an adaptation. More recent discussion within Korean-American communities, including from younger writers reflecting on their own identities, has also documented a countervailing trend: some Korean-Americans, especially those born or raised in the US, have chosen to go by their Korean given name as their primary or sole identifier rather than defaulting to an English one, treating the earlier generation's near-automatic adoption of an English name as a pattern worth reconsidering rather than simply continuing.
How this interacts with legal and immigration process
An adopted English given name of this kind is a matter of personal and family practice, not, by itself, a legal name change — a person using "John" socially and professionally can still hold a different legal given name on their birth certificate, Korean passport, or original immigration paperwork unless a formal legal step is taken to change it. US naturalization has, since 1906, offered a formal, documented mechanism for exactly this: US immigration records have required formal documentation of any such legal change made during the naturalization process since that year, and naturalizing citizens have long had the option, though never the obligation, to have it made official as part of the naturalization proceeding itself. That means an adopted English given name a person has used informally for years — in some cases decades — can become the person's actual legal name at the point of citizenship, converting what began as a practical, informal choice into the form that appears on every subsequent legal document, from a driver's license to a professional license to a diploma.
The practical result, for someone called John Kim specifically, is that the identity attached to a given person's professional and public record may be a purely social choice never made legally official, a form formalized decades ago during naturalization, or one a person has held from birth as a US-born child of Korean immigrant parents. All three produce an identical public-facing name, with nothing in it to indicate which path produced it.