Determined a time to employ staff after commercial (7)
I believe the answer is:
adamant
'determined' is the definition.
(I've seen this before)
'a time to employ staff after commercial' is the wordplay.
'time' becomes 't'.
'to employ' is an insertion indicator.
'staff' becomes 'man' (manning is a kind of staffing**).
'after' is a charade indicator (letters next to each other).
'commercial' becomes 'ad'.
'a'+'t'='at'
'at' placed around 'man' is 'amant'.
'amant' put after 'ad' is 'ADAMANT'.
(Other definitions for adamant that I've seen before include "Determined and unyielding to requests" , "Data man can be quite unyielding" , "Positive and unrelenting" , "Insistent, inflexible" , "Decided" .)