If I receive income from insurance commissions from past employment, but no longer work in insurance sales (Yes, I received a 1099-MISC), do I also need Schedule C?

[BMcCalpin]

Yes, since this 1099-MISC was from earned income, you will have to complete a Schedule C (Business) as if you were a sole proprietor. The purpose of this is not only to determine your federal income tax due, but also to determine your self-employment taxes (which are the Social Security and Medicare taxes that you see on your W-2). These will be found on Schedule SE, which is derived from the net profit on Schedule C.