He had to accept a curtailed role (6)
I believe the answer is:
harold
'he' is the definition.
'had to accept a curtailed role' is the wordplay.
'to accept' indicates putting letters inside.
'a curtailed' means to remove the last letter.
'role' with its final letter taken off is 'rol'.
'had' going around 'rol' is 'HAROLD'.
(Other definitions for harold that I've seen before include "Man's name" , "Last Anglo-Saxon king of England" , "Battle of Hastings loser" , "King of England 1037-40" , "Maybe Steptoe" .)