A boarder from Western Australia, Moore entered the Western Australian Parliament in 1904, becoming Premier two years later, aged 36. He remained in office until 1911 when he became WA's Agent General in London.
During WWI he was in charge of AIF camps and training in England with the temporary rank of Major General. In 1918 Newton Moore won the seat in the House of Commons vacated by former Australian Prime Minister Sir George Reid. He remained in the British Parliament until 1932.
Business interests, including the chairmanship of the Dominion Shell and Coal Corporation, took him to Canada, where he died in 1936.