Origins, Edwardian expansion and War-time contraction 
The firm was started by John Mackintosh (1868-1920) and his wife Violet (née Taylor), who bought a pastry shop in Halifax with their joint savings of £100 in 1890, the year that they married: Violet, who had been a confectioner's assistant before her marriage, ran the shop whilst John continued to work at a cotton mill. In order to attract customers they decided to sell a special toffee. Violet developed a recipe which blended the traditional, brittle English butterscotch with soft, American caramel  and they sold the toffee as Mackintosh's Celebrated Toffee. The toffee was very successful and Mackintosh was able to expand the business beyond Halifax by 1894. Indeed, it was so successful that it "ultimately transformed popular understanding of the term ‘toffee’, previously a description of any sugar or boiled sweet".
Moving from retail to manufacture and wholesale, they first rented a small warehouse in Bond Street, Halifax, and, in 1895, commenced larger scale production at bigger premises at Hope Street. The firm was converted into a limited liability company, John Mackintosh Ltd, in 1899 raising £11,000 and borrowing a further £4,000 to build a new works at Queen's Road. When this building was destroyed by fire in 1909, the insurance payout was used to purchase the vacant Albion Mills and the Queen's Road factory was rebuilt and 1912 expanded to begin chocolate manufacture.
In 1904 Mackintosh established his first overseas factory at Asbury Park, New Jersey which, however, soon failed. Undeterred, a factory was opened in 1906 at Krefeld, near Düsseldorf. By 1914, operations had been established in Australia and Canada and John Mackintosh Ltd employed some 1000 people.
The German factory was confiscated and the number of employees fell to 250 during the First World War. In 1917 a new line was developed, a chocolate covered Toffee-De-Luxe, but all chocolate production ceased that year when a war-time conscription tribunal refused an exemption for a key manager.
Power of publicity 
Mackintosh understood the power of marketing and publicity. He began with handbills advertising Mackintosh's Celebrated Toffee as a weekend treat targeting the Saturday afternoon market when workers had a half-holiday and their weekly wage payment in hand.  By 1896 Mackintosh was calling himself the "Toffee King"  and his product "The King of All the Toffees". In 1902 the firm began consumer and coupon competitions and then national press marketing: the firm bought space in the Daily Mail, Britain's most popular mass newspaper, and used story lines, graphics, and cartoons, when his competitors limited themselves to wordy descriptions.
Post-war restructure and growth beyond "Toffee Town" 
After John Mackintosh's death in 1920, his eldest son Harold Mackintosh took charge. The company was floated as John Mackintosh & Sons Ltd in March 1921. By paying the shareholders of the old company ordinary and preference shares (in a sum greater than the issued capital of John Mackintosh Ltd. together with a substantial distribution), they controlled some 93% of the new firm; two of the founders' sons, Harold and Douglas, controlled over half the ordinary shares. To pay estate duties, the public were offered some preference shares.
The family ownership was supplemented by some key management appointments: Harold Mackintosh, chairman and managing director, took charge of purchasing; (John) Harry Guy, a Quaker and a Price Waterhouse trained accountant, became finance director (from 1922 until his death in 1955); Frank Bottomley, an old school friend of Harold, became works manager (retiring from the firm in 1966); and marketing was overseen by E. L. Fletcher who joined the firm from the advertising agency T. B. Browne where he had worked on the Mackintosh account.
A series of surreal Heath Robinson cartoons of "Toffee Town" began a memorable national newspaper marketing campaign in October 1921. As the headquarters of the growing concern, Halifax became known as "Toffee Town".
Mackintosh re-entered the United States market but by 1931 it entered into an agreement with another Yorkshire company whose Toronto subsidiary manufactured its toffees on a royalty basis and exported them over the border to the United States.
The North Kerry Manufacturing Company was acquired when the firm's sales in the new Irish Free State were affected by import duties in 1924 and, in 1931, they merged their interests with Rowntree using a holding company, Associated Chocolate and Confectionery Company.
Acquisitions were also made in the British market. In 1927, the purchase of two confectionery retailers, Meeson and Tuckshop, gave the firm direct access to consumers, some control over retail prices and diversification. In 1929, the Anglo-American Chewing Gum Ltd. (later renamed Anglo-American Confectionery) expanded their product range and forestalled American entry into the British market with a rival chewing product.
The Caley Acquisition 
Albert Jarman Caley began selling a range of mineral waters and soft drinks in Norwich in 1863. He diversified to produce cocoa (1883), chocolate (1886) and Christmas crackers (1898). The business was purchased in 1918 by the African and Eastern Trading Company and underwent expansion at Norwich and mineral-water and cider factories in London, Ipswich, and Banham, Norfolk. Caley's had become over-capitalised and unprofitable and the new owner sought unsuccessfully to dispose of the business in the 1920s.
In 1920, Lever Brothers acquired the Niger Company and, in 1929, the United Africa Company was formed by a merger of the Niger Company and the African and Eastern Trading Company. In the same year, Unilever was formed when Lever Brothers merged with Dutch Margarine Unie.
Whilst continuing in their roles at the parent company, Eric Mackintosh (Harold's younger brother, managing director of Mackintosh's from 1929) became chairman of Caley's, Harry Guy took control of finance and Frank Bottomley as works manager.
Millie Mackintosh who is currently starring in Made in Chelsea is the heiress of the company.
Later developments 
- Robert Fitzgerald, ‘Mackintosh, John (1868–1920)’, Oxford Dictionary of National Biography, Oxford University Press, 2004; online edn, January 2010 accessed 29 January 2011 John Mackintosh (1868–1920): doi:10.1093/ref:odnb/38422 Archived 12 February 2011 at WebCite
- Toffee King John Mackintosh, 15 May 2008, Evening Courier.
- Robert Fitzgerald, "Markets, Management, and Merger: John Mackintosh & Sons, 1890-1969" (2000) 74 (no. 4) The Business History Review 555-609 accessed 29 January 2011
- "TOFFEE TOWN.". Cairns Post (Qld. : 1909-1954) (Qld.: National Library of Australia). 19 September 1950. p. 3. Retrieved 29 January 2011.
- The Caley's Story, Norwich Evening News.