Scorer from Harlem briefly in action (5)
I believe the answer is:
lehar
'scorer' is the definition.
(Austro-Hungarian composer Franz Lehar)
'harlem briefly in action' is the wordplay.
'briefly' means to remove the last letter.
'in action' indicates an anagram (I've seen this in other clues).
'harlem' with its final letter taken off is 'harle'.
'harle' is an anagram of 'LEHAR'.
'from' is the link.
(Other definitions for lehar that I've seen before include "Austrian of note" , "Franz . . . . . composed 'The Merry Widow'" , "Hungarian who composed" , "Viennese composer" , "He scored" .)