Sultan's alas misguided racket (7)
I believe the answer is:
saladin
'sultan's' is the definition.
(12th-century sultan)
'alas misguided racket' is the wordplay.
'misguided' indicates anagramming the letters (letters guided into the wrong places).
'racket' becomes 'din' (both can mean a loud noise or disturbance).
'alas' with letters rearranged gives 'sala'.
'sala'+'din'='SALADIN'
(Other definitions for saladin that I've seen before include "Muslim warrior" , "Richard the Lionheart's Crusade opponent" , "Crusade warrior" , "Enemy of Richard I in the Crusades" , "He fought Richard" .)