Fellow I had to hire is a restless type (6)
I believe the answer is:
fidget
'a restless type' is the definition.
'fellow i had to hire' is the wordplay.
'fellow' becomes 'f' (abbreviation - of a society etc.).
'i had' becomes 'I'd' (I'd).
'to hire' becomes 'get' (I am not sure about this - if you are sure you should believe this answer much more).
'f'+'id'+'get'='FIDGET'
'is' is the link.
Can you help me to learn more?
(Other definitions for fidget that I've seen before include "Restless person" , "Make small movements through nervousness or impatience" , "person always on the move" , "Make nervous movements of the hands" , "Squirm" .)