Shipowner and frozen-meat trade pioneer. Born in Ayr, McIlwraith was educated at the Academy there before joining his father's shipping business in 1868. He supervised the family's interests in Scotland while established trade relationships with his brothers, John (1828 - 1902) and Thomas (1835 - 1900), who had emigrated to Australia.
In 1875, he formed the shipping firm of McIlwraith, McEacharn & Company with Malcolm McEacharn (1852 - 1910) in London. Four years later, the pair became involved in shipping frozen meat with McIlwraith responsible for fitting out the steamer Strathleven, the first ship to successfully transport frozen meat from Australia to Britain. McIlwraith was also reorganised Tokyo's tramways.
He retired a wealthy man to Salcombe (Devon), where he died.
