[1] He was a member of the New South Wales Legislative Assembly from 1893 to 1898, winning the seat of Macleay as the Protectionist Party candidate at the 1893 by-election,[2] but it was abolished the following year and replaced by Hastings and Macleay which he won, holding it in 1895 and 1898.

Barton was a major driver in the Federation movement but as he lost his seat in the NSW Colonial parliament he faced exclusion from the discussions.

[4] He was later appointed a member of the New South Wales Legislative Council from 1899–1900, representing the Protectionist Party.

[5] He held the seat until his defeat in 1903 by Henry Lee of the Free Trade Party.

On 21 December 1933 he was granted permission to retain the title "The Honourable" because he had been a member of the first federal parliament.