He painted game in colour, retrospectively (5)
I believe the answer is:
durer
'he painted' is the definition.
(Albrecht Durer)
'game in colour retrospectively' is the wordplay.
'game' becomes 'ru' (rugby union).
'in' indicates putting letters inside.
'colour' becomes 'red' (red is a kind of colour).
'retrospectively' is a reversal indicator.
'ru' inserted into 'red' is 'rerud'.
'rerud' backwards is 'DURER'.
(Other definitions for durer that I've seen before include "Albrecht --, German engraver and artist" , "Albrecht -, C15-16 German artist" , "Albrecht --, German engraver/painter" , "Albrecht --, German painter and engraver" , "From Renaissance artist" .)