John Reddy was born on March 31, 1822, in Athlone, Ireland.

He was a physician. In 1848, he received his M.D. degree from the University of Glasgow, Scotland, and moved to Canada in 1851. He was licenced to practice in Quebec in 1852 and became House Surgeon and an attending physician at the Montreal General Hospital. He was a member of the Corporation of the Royal Institution for the Advancement of Learning and was elected President of the Montreal Medico-Chirurgical Society in 1874. Reddy also received an ad eundem M.D. from McGill University in 1856. Montreal’s Reddy Memorial Hospital (1870–1997) was named after John Reddy’s physician son, Herbert Lionel Reddy (1854-1936).

In 1851, he married Jane Fleming (1813–1878). He died on January 23, 1884, in Dublin, Ireland.

The Red River Settlement was a colonization project set up in 1811 by Thomas Douglas, 5th Earl of Selkirk (1771-1820) who was granted 300,000 square kilometres (120,000 square miles) of land the Hudson's Bay Company. Upon inheriting his father's title in 1799, Selkirk focused the majority of his time and resources on establishing a Scottish colony in North America. Selkirk was influenced by humanitarian luminaries such as William Wilberforce and, following the forced displacement of Scottish farmers that took place during the Highland Clearances, decided that emigration was the only viable option to improve the livelihood of the Scottish people. In July 1811 Miles MacDonell sailed from Yarmouth, England to the Hudson's Bay post at York Factory with 36 primarily Irish and Scottish settlers. Due to persuasive efforts of the North West Company only 18 settlers actually arrived at Red River in August 1812. Dogged by poor harvests and a growing population, MacDonell, now governor of Red River, issued the Pemmican Proclamation in January 1814 to prevent the export of pemmican from the colony. In doing so, MacDonell undermined the security of Red River and plunged the colony into a conflict with the North West Company that would not end until 1821.

On 11 June 1815, representatives of the North West Company attacked and fired upon the colonists, and demanded the surrender of Governor MacDonell, who, to avoid the loss of blood, gave himself up voluntarily. He was taken to Montreal as a prisoner, and charges were laid against him by his enemies, but his case was not tried.