Character played quietly for the wrong reason (7)
I believe the answer is:
persona
'character' is the definition.
(I know that character can be written as persona)
'played quietly for the wrong reason' is the wordplay.
I cannot quite see how this works, but
'quietly' could be 'p' (p for piano and quiet) and 'p' is located in the answer.
an anagram of 'reason' is 'ersona' which is within the answer.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for persona that I've seen before include "Theatrical role" , "Role adopted by actor" , "Public image" , "character on the stage?" , "One who is diplomatically acceptable" .)