If I bring a cashier's check from a bank in the US, will a Thai bank take that as a deposit?

I understand they may take a month or so to process it.

I understand the standard way is to wire the funds, but I have other reasons.

If you state what those reasons are, someone might be able to propose a third option.

I believe most banks accepts foreign check - as long as you are willing to wait for it to actually clear, accept a worse exchange rate than with wire and accepts the various fees involved. I would stick to the big/most international banks though; HSBC, Bangkok Bank Etc. if it was me. Cheers!

Many Thai banks have branches in the US, get a cashier's check from one of them, that could speed up things.