1715–74, British colonial leader in America, b. Co. Meath, Ireland. He settled (1738) in the Mohawk valley, became a merchant, and gained great power among the Mohawk and other Iroquois. He acquired large landed properties, founded (1762) Johnstown, N.Y., and lived in baronial splendor at Johnson Hall. Because of his influence with the indigenous population (he was made a Mohawk sachem in the 1740s), he was a key figure in the French and Indian Wars, first becoming prominent in King George's War. At the Albany Congress (1754) he helped formulate British policy toward native peoples, and he was made (1755) superintendent of Iroquois affairs. In the French and Indian War, although his expedition against Crown Point did not capture that fort, he soundly defeated (1755) the French under Baron Dieskau at Lake George and built Fort William Henry. Johnson was rewarded with a baronetcy.
In 1759 he captured Fort Niagara, and in 1760 he served with Gen. Jeffery Amherst in the capture of Montreal. He had been appointed general superintendent of Indian affairs north of the Ohio in 1756, and after the Peace of Paris (1763) his office was of great significance in the vast new areas gained from France. His chief lieutenants were George Croghan; Johnson's son-in-law, Guy Johnson; his son, Sir John Johnson; and Daniel Claus. Although Pontiac's Rebellion and British economy measures prevented him from establishing the centralized control over natives and fur traders that he desired, he did much to further British rule in the formerly French territories. He presided at the council of Fort Stanwix (1768). His papers have been edited by the New York State Division of Archives (13 vol., 1921–62).