In revolutionary China, run by Mao, mostly as leader (8)
I believe the answer is:
chairman
'leader' is the definition.
(chairman is a kind of leader)
'in revolutionary china run by mao mostly' is the wordplay.
'in' is an insertion indicator.
'revolutionary' indicates anagramming the letters.
'run' becomes 'r' (cricket abbreviation**).
'by' means one lot of letters go next to another.
'mostly' means to remove the last letter.
'china' with letters rearranged gives 'chain'.
'mao' with its final letter taken off is 'ma'.
'r'+'ma'='rma'
'chain' placed around 'rma' is 'CHAIRMAN'.
'as' is the link.
(Other definitions for chairman that I've seen before include "Head of the board" , "A leader of meetings" , "Sedentary male of a committee" , "Presiding official" , "Top person on a committee - this one's male" .)