Tracking the very last call result of a contact

Forgive me if I'm posting in the wrong spot!

We have an added custom fields for calls that allow a user to select "TT" for Talk To, "LM" for "Left Message",  "Scheduled Call" and "Ops Note". It helps give us a better idea of which clients are picking up the phone vs not. 

My sales director wants me to provide her a report of all of our current clients and their last call result. (not the last call, but the result. LM, TT, Ops Not, etc) This has proven difficult.

In theory, I think I need to create another field and perhaps a workflow that would occur when the record is saved and update the new field with the newest call result. (I already created a workflow that documents that last phone call date/time stamp but now I need a separate field that shows the last call result)


Does anyone have an idea on how I can accomplish this?

Thank you so much!