Can I keep my remote job from home while on a D-4?

You get vague answers because the situation is genuinely a grey area in Korean law, and anyone giving you a confident yes or no is overstating what is settled. Here is the honest position.

What is clear:

1. The D-4 permits study. Any work performed in Korea requires the part-time work permit, and that permit covers employment with a Korean employer.

2. Immigration's framework was written around physical employment in Korea. Remote work for a foreign employer, paid abroad into a foreign account, with no Korean client, no Korean income and no Korean employer, is not what that framework was built to address.

3. There is no explicit prohibition on continuing pre-existing remote employment for a foreign company, and there is also no explicit permission. Enforcement against students in this position is not something we see in practice, but "rarely enforced" is not the same as "permitted".

What increases risk:

- Any Korean client or Korean-sourced income. This moves you clearly into territory that requires authorisation.
- Being paid into a Korean account for work.
- Spending long enough in Korea to trigger tax residency — generally 183 days in a tax year — at which point your worldwide income may become reportable in Korea. This is a tax question separate from the visa question and it catches people.
- Anything that looks like running a business from Korea.
- Letting the work affect your attendance. This is the thing that actually gets noticed, because attendance is what immigration checks.

What we would say to a student in your position: the arrangement you describe — foreign employer, foreign payment, pre-existing job, no Korean connection — is the lowest-risk version of this and is very common among students. Keep it that way, keep your attendance above 90 percent, and do not take Korean clients.

And because this is genuinely unsettled: if the income is significant or you plan to stay past a year, this is worth a paid consultation with a Korean immigration lawyer or a licensed administrative scrivener (행정사). That is a small cost against the size of the thing you would be risking, and it is the only way to get an answer you can rely on rather than a forum consensus.