Artist first providing support for military show (9)
I believe the answer is:
tattooist
'artist' is the definition.
(I've seen this before)
'first providing support for military show' is the wordplay.
'first providing' becomes 'ist' (I am not sure about this - if you are sure you should believe this answer much more).
'support for' says to put letters next to each other.
'military show' becomes 'tattoo' (I've seen this before).
'ist' after 'tattoo' is 'TATTOOIST'.
Can you help me to learn more?
(Other definitions for tattooist that I've seen before include "Skin decorator" , "permanent marker?" , "Designer" , "Skin artist" , "Sort of marksman" .)