Hello,
a more detailed Blowup picture of the medal (and the collar insignia if there are any) could shed some light
on the army in which this gentleman was serving...
If there are three stars on the collar, then it is no doubt a US General-
but who? - Confederate or Union? You will have to browse a lot of Portraits...
There are some Pairpoint (end 19th Cent.) sulphides around, showing Secession War Generals,
for the medal, there is the Kearny Cross (straight arms), which can be a hint,
the Iron Cross has curved arms, hope this helps,
Kind regards, Erhard