He was educated at Street John"s College, Cambridge.
Rolph remained in England, studying law at the Inner Temple in London. He arrived in Upper Canada during the War of 1812 and served as the paymaster for the London District militia. In 1817, he resumed his education in England, studying law and medicine.
He was called to the bar in England in 1821 and returned to Upper Canada in the same year and was also called to the bar there.
In 1824 he established the first medical school in Upper Canada with Doctor Charles Duncombe in Saint Thomas, under the patronage of Colonel Thomas Talbot. In 1824, he was elected to the 9th Parliament of Upper Canada to represent, along with John Matthews, Middlesex County.
In politics, Rolph aligned himself with the Reformers. He supported allowing American-born settlers in Upper Canada being given all the rights of British subjects.
He spoke for the separation of Church and State and against imprisonment for debt.
In 1835, he helped found the Bank of the People and served as its first president In 1832, he moved to York (Toronto) and was elected to town council in 1834 representing Saint Patrick"s Ward. He resigned from council after he turned down the position of mayor.
In February 1836, he was appointed to the Executive Council of Upper Canada by the new lieutenant governor Sir Francis Bond Head and he resigned the next month when the governor chose to ignore the opinions of the council.
Although Rolph was aware of the preparations for the Upper Canada Rebellion, he did not advise the authorities and he expected to be part of a new government if the rebellion had been successful. He advised the rebels to advance their time table when he learned that William Lyon Mackenzie was to be arrested.
On December 5, with Robert Baldwin, he carried a message to the rebel leaders from the lieutenant governor under a flag of truce, advising them to return home. On December 6, fearing that his involvement would soon be discovered, he fled to the United States.
He was expelled from the legislature in January 1838.
After spending several years in Rochester, New York, he returned to Toronto in 1843 after being granted amnesty. In 1851, he was elected to represent Norfolk County in the Legislative Assembly and was appointed Commissioner of Crown Lands (serving 28 October 1851 – 30 August 1853). He also established a medical school, the Toronto School of Medicine.
In 1854, the school became affiliated with Victoria College in Cobourg.
He suffered a stroke in 1861 and finally retired in 1870. He died in Mitchell, a short time later.
In 1826, he became a member of the Royal College of Surgeons of England and, in 1829, was licensed to practise medicine in Upper Canada.