[1][2] Born at Peterville in Kings County, Prince Edward Island, McIntyre's paternal grandfather came to Canada from Scotland around 1785 and settled at Cable Head, PEI.

McIntyre's great-grandfather on his mother's side fought under General Wolfe at the Battle of the Plains of Abraham in 1759.

[1] Following Prince Edward Island's entry into Canadian confederation which occurred, in part, as a result of the debt incurred by the colony for the railway's construction, McIntyre was elected in the 1874 federal election to the House of Commons of Canada as a Liberal Member of Parliament for Kings County.

He was defeated in the 1878 federal election but regained his seat in 1882 and was re-elected in 1887.

[2] After being defeated in the next two elections,[2] McIntyre was appointed the seventh Lieutenant Governor of Prince Edward Island by the Laurier government in 1899.