He was born in Newark to Allan MacNab and Anne Napier. When MacNab was a one year old, he was baptized in the Anglican church in St. Mark's Parish of Newark. His father was a lieutenant in the 71st Regiment and the Queen's Rangers under Lt-Col. John Graves Simcoe. After the Queen's Rangers were disbanded, the family moved around the country in search of work and eventually settled in York, where MacNab was educated at the Home District Grammar School. As a fourteen-year-old boy, he fought in the War of 1812. He probably served at the Battle of York and certainly as the point man in the Canadian forlorn hope that headed the Anglo-Canadian assault on Fort Niagara. The 20 local men eliminated two American pickets of 20 men each with the bayonet before taking part in the final assault. Captain Kerby, of the Incorporated Militia Battalion, was reportedly the first man into the fort. After the war, he studied law in Toronto and was admitted to the bar in 1824. In 1826, MacNab moved from York to Hamilton, where he established a successful law office, but it was chiefly by land speculation that he made his fortune. There was no Anglican church in Hamilton yet, so MacNab attended a Presbyterian church until Christ Church was established in 1835.
Political career
In 1830, he was elected to represent the city in the Legislative Assembly of Upper Canada, a position that he held for some 27 years. As a member of the legislature, MacNab opposed the reform movement in Upper Canada that was led by William Lyon Mackenzie. When Mackenzie led the Upper Canada Rebellion in 1837, MacNab was part of the British militia that moved against Mackenzie at Montgomery's Tavern in Toronto on 7 December, dispersing Mackenzie's rebels in less than an hour. On 29 December, MacNab and Captain Andrew Drew, of the Royal Navy, commanding a party of militia, acting on information and guidance from Alexander McLeod, attacked Mackenzie's supply ship at Navy Island. The sinking of the SS Caroline became known as the Caroline affair. MacNab then led a militia of his own against the rebels marching towards Toronto from London, led by Charles Duncombe. Duncombe's men also dispersed when they learned that MacNab was waiting for them. In 1838, he was knighted for his zeal in suppressing the rebellion. He served in the Legislative Assembly of the Province of Canada, leading the province from 1854 to 1856. He was elected to the Legislative Council of the Province of Canada in 1860, representing Western Division until his death. When Parliament met at Montreal, MacNab took apartments there at Donegana's Hotel. . A successful entrepreneur as well as politician, MacNab, with Glasgow merchant Peter Buchanan, was responsible for the construction of the Great Western Railway.
MacNab died at his home, Dundurn Castle, in Hamilton. His deathbed conversion to Catholicism caused a furor in the press in the following days. The Toronto Globe and the Hamilton Spectator expressed strong doubts about the conversion, and the Anglican rector of Christ Church declared that MacNab died a Protestant. However, MacNab's Catholic baptism is recorded at St. Mary's Cathedral in Hamilton, at the hands of John Farrell, Bishop of Hamilton, on 7 August 1862. When the 12th Chief of Clan Macnab died, he bequeathed all his heirlooms to MacNab, whom he considered the next Chief. When the latter's son was killed in a shooting accident in Canada, the position of Chief of Clan Macnab passed to the Macnabs of Arthurstone.
Legacy
and Sir Allan MacNab Secondary School in Hamilton, Ontario are both named after him. Dundurn Castle, his stately Italianate style home in Hamilton, is open to the public. A ship was named Sir Allan MacNab and was sturdily built in Canada but was not altogether designed for speed. The master in 1855 was Captain Cherry, and the tonnage of the ship was 840, then quite large. The ship was named after the Canadian hero and statesman.