Person longing — not the first — for something profitable (6)
I believe the answer is:
earner
'something profitable' is the definition.
'person longing not the first' is the wordplay.
'person longing' becomes 'yearner'.
'not the first' means to remove the first letter.
'yearner' with its first letter removed is 'EARNER'.
'for' is the link.
(Other definitions for earner that I've seen before include "One paid for work" , "Employed person" , "Employee" , "lucrative job" , "One receives wages in return for labour" .)