Born in Fremantle and trained as a surveyor he worked in the South West and was an officer in a volunteer Light Horse Regiment. Mayor of Bunbury in 1901-04, he was elected as the Member for Bunbury in 1904 and in 1905 became Minister for Lands and Agriculture in the Rason Liberal Government. When Rason resigned he was elected Liberal leader and became Premier aged 35. Newton Moore's government laid the foundations of the Wheatbelt and brought the State into line with the rest of Australia through an Income and Land tax, despite opposition from the conservative Legislative Council.
In 1908 Newton Moore led the Liberal Party to a second election victory, despite the loss of some seats to the ALP. However the strain of office took a toll on his health and he resigned as Premier in 1910. The following year he left Parliament to become Agent General in London, serving 1911-17. During the First World War, as a Major General, he commanded the AIF troops in based in Britain and in 1918 was invited by the Conservative Party to stand for the House of Commons in the seat formerly occupied by ex-Australian Prime Minister George Reid. From 1918 until 1932 Moore represented the Conservatives in Parliament for several London seats, and was a company director with interests in WA and in Canada. He was easily the most outstanding Premier since Forrest, like him a surveyor and MLA for Bunbury.