He presents a Gallic person nursing child (9)
I believe the answer is:
anchorman
'he' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'a gallic person nursing child' is the wordplay.
'gallic person' becomes 'norman' (I am not sure about this - if you are sure you should believe this answer much more).
'nursing' indicates putting letters inside.
'child' becomes 'ch' (abbreviation for child).
'norman' placed around 'ch' is 'nchorman'.
'a'+'nchorman'='ANCHORMAN'
'presents' is the link.
Can you help me to learn more?
(Other definitions for anchorman that I've seen before include "host" , "One broadcasting" , "Maybe last person to run" , "Last person in relay race - TV presenter" , "Crucial participant" .)