https://familysearch.org/ark:/61903/3:1:33S7-9GY4-QKJ?i=2448&wc=M6Z6-SWG%3A171467701%2C171467702&cc=1874474

Should take you to the pension record and a newspaper article about William's servant Sam, that accompanied him to the army.

I can't find a record for a Lieutenant William Newsome, killed at Chickamauga. I assume he served in a Tennessee regiment ? Sam received his pension at 100 years old. He was granted a pension following a "personal interview". Only time I've ever seen that, but I can't find this soldier.