He was born in the Mohawk Valley in New York state in 1777, the son of a Scottish immigrant who was a loyalist during the American Revolution. John came to Upper Canada sometime between 1795 and 1801 and settled in Matilda Township, now part of South Dundas Township.
While clearing his property, John discovered a number of seedling apple trees growing wild. He transplanted them to his garden, and by the following year only one had survived.
Several years later, the tree was producing the crisp, delicious fruit that everyone is familiar with today. The discoverer eventually dubbed it the "McIntosh Red", which is still the apple's official name. For years, he had no luck propagating the variety because apples don't grow true from seed.
Chance again played a role in 1835 when he and his son, Allen, learned from a visitor the art of grafting cuttings or scions from the original tree. With this cloning technique at their disposal, production of the McIntosh Red could finally branch out.
By the late 1830s, Allen and his brother Alexander ("Sandy") had taken over the farm operation from their father. From their well organized nursery, they extensively promoted and nurtured the new species. However, it wasn't until the turn of the 20th Century that conditions really began to improve for the McIntosh, with the advent of fungicidal sprays that countered its natural susceptibility to apple scab. Market penetration grew and grew, and today, millions of McIntosh apple trees are in production. The Mac and its hybrids account for more than 50 percent of the apple crop in Canada.
McIntosh family history states that among the apples on the farm, one tree produced apples far superior to any other tree. An itinerant farmhand showed Hannah McIntosh (John's wife) how to perform grafting, and this she did to great success. John was a travelling preacher and used to take the apples with him on his rounds. Hannah then taught Allen the art of grafting and the rest (as they say) is history. While women were never given credit for discoveries or inventions in times past, perhaps it is time to give credit where credit is due and give Hannah some. The original name of the apple John distributed was "Granny's Apple"... perhaps recognizing Hannah at first.
In 2001 the Historic Sites and Monuments Board of Canada unveiled another plaque in a nearby park and declared the apple's discovery and development an "event of national historic importance." The park, which belongs to the Township of South Dundas, also features a large hand-painted mural depicting the apple's history.
William Tyrrell Macoun of the Central Experimental Farm in Ottawa is credited with popularizing this variety of apple in Canada. Other apple varieties derived from the McIntosh include the Macoun and Cortland.