Quick-witted stage hero bags one grand in card game (6)
I believe the answer is:
figaro
'quick-witted stage hero' is the definition.
(character in the opera The Marriage of Figaro)
'one grand in card game' is the wordplay.
'one' becomes 'i' (Roman numeral).
'grand' becomes 'g' (G is short for grand as in a thousand).
'in' indicates putting letters inside.
'card game' becomes 'faro' (faro is a kind of card game).
'i'+'g'='ig'
'ig' put into 'faro' is 'FIGARO'.
'bags' is the link.
(Other definitions for figaro that I've seen before include "Hero of Mozart opera" , "Beaumarchais hero" , "Mozart tells of his operatic marriage" , "The Barber of Seville" , "Mozart opera 'The Marriage of . . . . . .'" .)