Not initially happy to be hired (6)
I believe the answer is:
leased
'hired' is the definition.
(I know that hired can be written as leased)
'not initially happy' is the wordplay.
'not initially' means to remove the first letter.
'happy' becomes 'pleased' (similar in meaning).
'pleased' with its first letter removed is 'LEASED'.
'to be' is the link.
(Other definitions for leased that I've seen before include "Rented" , "Let for money" .)