Herald procures cracking editor at last (9)
I believe the answer is:
precursor
'herald' is the definition.
('precursor' can be a synonym of 'herald')
'procures cracking editor at last' is the wordplay.
'cracking' indicates an anagram.
'at last' says to take the final letters.
The final letter of 'editor' is 'r'.
'procures' anagrammed gives 'precurso'.
'precurso'+'r'='PRECURSOR'
(Other definitions for precursor that I've seen before include "Something going in advance of another" , "Herald" , "One coming before" , "I was here first" , "Forerunner, predecessor" .)