Buying a mortgage note from someone: is that a licensed act?

Also unclear whether it matters if I buy it in my own name versus an LLC. Every article I find talks about originating loans, not buying existing ones.

The rough shape of it, and you need a lawyer in the actual state to confirm, is that a bunch of states license mortgage loan purchasers and servicers separately from originators, and owner-occupied residential paper is where the rules bite hardest. Business-purpose and commercial notes are generally treated more loosely. Hiring a licensed servicer covers the servicing side and does not automatically cover you for holding the loan. Some states care about the holder, some only about the servicer. It genuinely varies state by state, so the answer for a note in one state tells you nothing about the next one.

@rigging the LLC question doesn't change the licensing analysis much, an entity needs the same license a person would. What it changes is liability and how the assignment gets recorded, and if you form the entity in one state and the property is in another you may need to register there to bring a foreclosure. That last part catches people. Get a real estate attorney licensed where the property sits to look at it before you fund, not after the borrower stops paying.