 Sieber was severely wounded on July 2, 1863 in the Battle of Gettysburg, at Cemetery Ridge.He fought in several key engagements, including Battle of Antietam, Battle of Fredericksburg, Battle of Chancellorsville, Battle of Gettysburg, Apache Wars, Battle of Cibecue Creek, and Battle of Big Dry Wash. After the war, he became a prospector in California, Nevada, and in Arizona Territory, where he managed a ranch from 1868 to 1871.In July 1871, General George Stoneman hired Sieber as Chief of Scouts and for much of the Apache Wars.