Hi Michael
I do agree with Dave, make sure that you have a plan for post before shooting.
I have been able to “key” a white background before, but it will depend on what your footage is like. If you duplicate your footage layer in your comp, make the top layer high contrast black and white to use it as a track matte for the layer below. That way you don’t have to worry about messing up your actual footage or worry about keying out lighter parts of the actor. Again, it will depend on what your footage is like, but it may be what you are looking for.
Hope that makes sense!
-Jessica