Joyful story upset newspaper boss (6)
I believe the answer is:
elated
'joyful' is the definition.
(synonyms)
'story upset newspaper boss' is the wordplay.
'story' becomes 'tale' (synonyms).
'upset' shows that the letters should be reversed in order.
'newspaper boss' becomes 'ed' (short for editor).
'tale' written backwards gives 'elat'.
'elat'+'ed'='ELATED'
(Other definitions for elated that I've seen before include "Euphoric" , "Jubilant, quite chuffed" , "In very high spirits, really chuffed" , "Overjoyed, really delighted" , "Hyped up" .)