Show inmate reforming getting parole at last (7)
I believe the answer is:
matinee
'show' is the definition.
(I know that matinee is a type of histrionics)
'inmate reforming getting parole at last' is the wordplay.
'reforming' indicates anagramming the letters.
'getting' is an insertion indicator.
'at last' indicates one should take the final letters.
The final letter of 'parole' is 'e'.
'inmate' with letters rearranged gives 'matine'.
'matine' going around 'e' is 'MATINEE'.
(Other definitions for matinee that I've seen before include "Afternoon showing of play" , "First jackets" , "theatre performance" , "Afternoon theatre" , "early "performance"" .)