Performer, tenor, is in role (not lead) (6)
I believe the answer is:
artist
'performer' is the definition.
(eg a musician)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for artist that I've seen before include "Bacon, for example?" , "Constable, perhaps" , "eg Monet" , "One engaged in painting" , "Rousseau perhaps" .)