Miner was born Ezra Allen Miner in Vevay Township, near Onondaga, Ingham County, Michigan on December 27, 1846. He never legally changed his first name (which he evidently didn't like), but regarded William Allen Miner as his true name throughout most of his life. He was arrested for the first time in 1866 in San Joaquin County, California and served time there. He was shortly released but served more time at Placer County, California and later at Calaveras County, California. He was discharged in 1880. He then formed a partnership with Bill Leroy (as W. A. Morgan) to rob a stagecoach. Leroy was caught and lynched, but Miner escaped. He was later caught for another robbery in Tuolumne County, California and was released from San Quentin in 1901.