James Bell Johnston of East Angus, Quebec, a Canadian who graduated in medicine at University of Edinburgh, in 1833. He was the first doctor to establish a practice in Sherbrooke, Quebec. He is the father of Wyatt Galt Johnston (M.D., C.M., McGill, 1884).

John Johnston was born on August 25, 1762, in Belfast, Ireland, and died on September 22, 1828, in Sault Ste. Marie, Michigan. His parents were William Johnston of Portrush (Northern Ireland) and Elizabeth McNeil, and he belonged to an upper-class Scots-Irish family. He oversaw Belfast’s waterworks in 1778 and 1779 and travelled to Montreal in 1790. In 1791, he voyaged to La Pointe, on Lake Superior’s southern shore near present-day Ashland, Wisconsin, as a fur trader for the firm Todd, McGill, and Company. Here, he met the Ojibwe and learned their language and traditions. He befriended Waubojeeg (White Fisher) who was the Chief and he married Waubojeeg’s daughter, Ozhaguscodaywayquay (Woman of the Green Glade). She was given the name Susan after they married in Fort St. Joseph, and they had eight children together. Their marriage provided the grounds for a trading alliance between the North West Company and the Ojibwe of La Pointe. In 1793, Johnston established himself at Sault Ste. Marie, Michigan, as an independent trader. In 1808, he became a member of the Beaver Club and between 1814 and 1816 he received a commission of the peace. During the War of 1812, Johnston joined a small British force and took part in the capture of Mackinac Island and later defended Mackinac Island for the Americans.

Robert Bruce Johnston was born on April 29, 1835, in Leith, Midlothian, Scotland. He was a Writer to the Signet, a member of the Society of Writers to Her Majesty's Signet. From 1868 to 1888, he served as a Procurator Fiscal of Edinburgh. In 1864, he married Agnes Cockburn Smith (1844–1924). He died on February 4, 1888, in Edinburgh, Scotland.

Wyatt Galt Johnston was born in Sherbrooke in 1863. His father, Dr. J.B. Johnston, was a well known physician in the Eastern Townships. W.G. Johnston received his M.D., C.M. from McGill University in 1884. He succeeded William Osler as Pathologist at the Montreal General Hospital after the latter left for Philadelphia. He kept that position until his death in 1902. In 1886 he joined the Faculty of Medicine of McGill as Demonstrator in Pathology. Johnston also held positions in Bacteriology, Medico-Legal Pathology, Public Health and Preventive Medicine, Medical Jurisprudence, and Hygiene.

Johnstone served in the 3rd Ceylon Regiment.