Parker was educated as a lawyer, but being an American Indian had been unable to sit before the bar, as he was not a U. S. citizen. He later became an engineer for the U.S. Treasury Department and was sent to Galena, Illinois to supervise the construction of the customhouse.
In Galena, Parker met U. S. Grant, an obscure ex-army captain working as a clerk in his brother’s store. The two men became friends and during the war Grant made a position on his staff for the able Parker. At the time of the surrender Parker was a lieutenant colonel, but received the rank of brevet brigadier general after the Civil War.
Lieutenant Colonel Ely Parker made the formal ink copy of General Grant’s letter that spelled out the terms of surrender. “Having finished it, I brought it to General Grant, who signed it, sealed it and then handed it to General Lee” - Lt. Colonel Ely Parker.
At the surrender meeting, seeing that Parker was an American Indian, General Lee remarked to Parker, “I am glad to see one real American here.” Parker later stated, “I shook his hand and said, 'We are all Americans'.”
Among members of Grant’s staff Parker was known for his fine handwriting, his knowledge of the law, his sense of humor, and as a good fellow to have around in a fight. Parker once described himself as “a savage Jack Falstaff of 200 weight.”