Funny rebuke about person who did good work a hundred years ago, a comic genius (6,6)
I believe the answer is:
buster keaton
'a comic genius' is the definition.
(comic actor)
'funny rebuke about person who did good work a hundred years' is the wordplay.
'funny' indicates an anagram.
'about' is an insertion indicator.
'person who did good work' becomes 'st' (abbreviation for saint).
'hundred years' becomes 'ton' (I am not sure about this - if you are sure you should believe this answer much more).
'rebuke' is an anagram of 'buerke'.
'buerke' going around 'st' is 'busterke'.
'busterke'+'a'+'ton'='BUSTER KEATON'
'ago' is the link.
This may not be correct. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for buster keaton that I've seen before include "silent clown - with 21d" , "Broken statue (anag) - early film star" , "Silent screen star" , "Silent film comedy star, d. 1966" , "Comic" .)