Robertson was elected to Parliament in 1856 supporting manhood suffrage, secret ballot, electorates based on equal populations, abolition of state aid to religion, government non-denominational schools, free trade, and land reform.

Subsequently, on the advice of Sir Thomas Brisbane, the then Governor of New South Wales, the family emigrated to Australia, arriving on the "Providence" on 8 January 1822.

They were apparently in good circumstances, for, according to the custom of the time, anyone bringing to the colony a sum of not less than £2,500 was entitled to a first class grant of 2500 acres (10 km2) of land, and this they received in the Hunter Valley.

[1] James Robertson senior worked as a watchmaker and silversmith, and became Supervisor of Governor Brisbane's astronomical instruments and clocks at the government observatory in the Parramatta Domain.

[citation needed] On leaving school about the year 1833 Robertson went to sea and worked his passage to England where, through the medium of some letters of introduction, he accidentally came in contact with Lord Palmerston.

He made himself prominent in the struggle between the squatters and Governor Sir George Gipps, who attempted to restrict the expansion of grazing in northwestern New South Wales.

[citation needed] With the establishment of responsible government in 1856, Robertson stood for the Legislative Assembly seat of Phillip, Brisbane and Bligh, promising manhood suffrage, secret ballot, electorates based on equal populations, abolition of state aid to religion, government non-denominational schools, free trade, and free selection of crown lands before survey.

He was largely responsible for amending the electoral law to introduce adult male franchise, increase Legislative Assembly seats from 54 to 80, although eight of these were abolished when Queensland separated in late 1859.

This enabled him to obtain a dissolution from Governor Denison and to fight an election on the issue in December, which gave him a clear majority in the Legislative Assembly, all the candidates who publicly opposed land reform having been defeated.

He resigned from Parliament to sort out his financial difficulties through the failure of some properties he held in northern Queensland in October 1865,[1] but he was renominated to fill the vacancy eight days later.

[2] In January 1868, holding the offices of Premier and Colonial Secretary, Robertson formed his second ministry and he won back West Sydney in the December 1869 general election.

A committee was formed to raise and invest funds to sort out his financial problems and he won back West Sydney in March and discharged his bankruptcy in August.

He was a trustee of the Royal National Park and he injured his leg while working on it, which increased his depression and this together with his poor finances led him to retire from parliament in June 1886.

He was strongly against federation, largely on the grounds it would amount to the annexation of News South Wales by the other colonies, and led the Sydney campaign against the constitutional convention of 1891.

[1][2] One of his daughters, Margaret-Emma, married the Russian scientist and explorer Nicholas Miklouho-Maclay,[6] who built the first Marine Biological Station in Australia at Watsons Bay.