He studied at the training college and at the University of Adelaide, and rose to be first assistant at the Sturt Street School, Adelaide. He returned to Tasmania in 1886, studied law, and was admitted to the bar in 1892.
He was educated at the Derwent School, Hobart, and went to South Australia in 1879 entering the education department as a pupil teacher. He succeeded in re-organising the education department and established a training college at Hobart, but most of his party"s attempts to bring in democratic legislation were blocked by the Tasmanian Legislative Council. Propsting resigned on 11 July 1904 and was leader of the opposition until December 1905.
This ministry resigned in June 1909.
From April 1916 to August 1922 Propsting was attorney-general and minister for railways in Sir West. H. Lee"s ministry, and was attorney-general in the Hayes ministry which succeeded it until August 1923. He was elected president of the legislative council in July 1926 and held this position with distinction until his death at Hobart on 3 December 1937.
In February 1899 Propsting entered politics as member for Hobart in the Tasmanian House of Assembly, and in August 1901 was elected leader of the opposition. He became premier and treasurer on 9 April 1903, his party being known as the liberal democratic party.
He was then elected a member of the legislative council, and in May 1906 joined the Sir John West. Evans ministry as attorney-general and minister for education.