Original American way of working upset China (7)
I believe the answer is:
mohican
'original american' is the definition.
(ie a Native American)
'way of working upset china' is the wordplay.
'way of working' becomes 'mo' (I've seen this in other clues).
'upset' is an anagram indicator.
'china' with letters rearranged gives 'hican'.
'mo'+'hican'='MOHICAN'
(Other definitions for mohican that I've seen before include "striking style" , "A Native American people" , "The last one was celebrated in novel" , "elevated style" , "Punk style" .)