Film director ultimately one always after introduction to Ronnie Barker (9)
I believe the answer is:
retriever
'barker' is the definition.
(I've seen this before)
'film director ultimately one always after introduction to ronnie' is the wordplay.
'film director ultimately' becomes 'ret' (I am not sure about this - if you are sure you should believe this answer much more).
'one' becomes 'i' (Roman numeral).
'always' becomes 'ever' (synonyms).
'after' is a charade indicator (letters next to each other).
'introduction to' says to take the initial letters.
The initial letter of 'ronnie' is 'r'.
'i'+'ever'='iever'
'iever' put after 'r' is 'riever'.
'ret'+'riever'='RETRIEVER'
Can you help me to learn more?
(Other definitions for retriever that I've seen before include "Large hunting 11" , "Dog bred to fetch game" , "Breed of dog" , "making a complete recovery?" , "someone to set the situation right?" .)