My great grandfather disappeared in 1930 and the only record I have of him is these photos. He fathered my grandmother in 1914 in Australia and had a second family in the late 1920's. I have only just discovered his second family via ancestry DNA testing. His grand daughter provided me with the photos. I can tell that he's a musician but I don't know what branch of the services he was in. I can only assume that it's a US uniform as it appears to resemble a First World War uniform.
There's not much that can be said that hasn't already.
That's the uniform of a enlisted United States Army "doughboy". The uniform dates from between the first and second world wars.
The insignia is that of the US Army Band.
Note: The above insignia is "band leader". I assume the star above is the reserved for band leader.
That's as much as I can get without more details. I recommend you make a request to the US National Archives, you should be able to get details about your great grandfather.
Thanks very much for all of your help. I have discovered that he had another family in the US which means I now have more cousins. I'll try through army records to see what info they have on him, assuming he didn't change his name. Jan 23, 2018 at 21:31
USon the collar, he was a bandsman in the Regular Army..
U.S., I believe.