Consort with, ultimately, American gang (7)
I believe the answer is:
husband
'consort' is the definition.
(husband is a kind of consort)
'with ultimately american gang' is the wordplay.
'ultimately' says to take the final letters.
'american' becomes 'us'.
'gang' becomes 'band' (I've seen this before).
The final letter of 'with' is 'h'.
'h'+'us'+'band'='HUSBAND'
(Other definitions for husband that I've seen before include "Better half's other half?" , "Partner; use carefully" , "Spouse - save" , "Conserve" , "manage thriftily" .)