Parker first worked as a teacher at Spencer Academy and Armstrong Academy. In 1906 he attended the 1906 Oklahoma Constitutional Convention, where the states constitution was developed. As a member of the convention, Parker led design of the Seal of Oklahoma, earning the nickname "Great Seal Parker". Parker later served as Register of the Treasury from 1913 to 1914. His appointment was reported as marking the first time a Native American held the post.[5]
Parker died from a heart attack at his home in Oklahoma City on May 8, 1953, a few hours after hearing of his son's death from a heart attack in England on the same day.[6]