Founded in 1869 by John James Sainsbury with a shop in Drury Lane, London, the company was the largest UK retailer of groceries for most of the 20th century.

Food was rationed, and one particular shop in East Grinstead was so badly damaged on Friday 9 July 1943 that it had to move to the local church, temporarily, while a new one was built.

It was at the time the largest ever flotation on the London Stock Exchange;[22] the company rewarded the smaller bids for shares in order to create as many shareholders as possible.

The first SavaCentre shop was opened in Washington, Tyne and Wear, in 1977;[28] nearly half the space, amounting to some 35,000 sq ft (3,300 m2), was devoted to textiles, electrical goods and hardware.

[29] Sainsbury's diversified further in 1979, forming a joint venture with the Belgian retailer, GB-Inno-BM, to set up a chain of do-it-yourself shops under the Homebase name.

[41] Also that year, David Sainsbury dismissed Tesco's clubcard initiative as 'an electronic version of Green Shield Stamps'; the company was soon forced to backtrack, introducing its own Reward Card eighteen months later.

[44] In addition to Shaw's, Sainsbury's bought a minority stake in another supermarket group, Giant Food, based in Washington, DC,[45] although this shareholding was subsequently sold when Ahold of the Netherlands made a full bid for the company.

[46] An arrangement in late 1995 with Supermarket Direct made Sainsbury's the first major grocery retailer in the UK to offer a home delivery service.

[56] On 8 October 1999, the CEO Dino Adriano lost control of the core supermarket business within the United Kingdom, instead assuming responsibility for the rest of the group.

[59] In his first two years, he exceeded profit targets, although by 2004 the group had suffered a decline in performance relative to its competitors and was demoted to third in the groceries market within the United Kingdom.

Davis also oversaw an almost £3 billion upgrade of shops, distribution and IT equipment, entitled 'Business Transformation Programme', but his successor would later reveal that much of this investment was wasted and he failed in his key goal – improving availability.

[65] Schooled in Solihull near Birmingham, and a graduate of the University of Bath, where he took a business administration degree, King was also previously a managing director at Asda with responsibility for hypermarkets.

This reaffirmed the commentary of retail analysts: the group was not ensuring that shelves were fully stocked, due to the failure of the IT systems introduced by Peter Davis.

[83] He believed any offer at that stage of Sainsbury's recovery was likely to undervalue the business,[82] and with private equity seeking high returns on their investments, saw no reason to sell, given that the current management, led by Justin King, could deliver the extra profit generated for the benefit of existing investors.

[84] He claimed the bid 'brought nothing to the business', and that high levels of debt would significantly weaken the company and its competitive position in the long term, which would have an adverse effect on Sainsbury's stakeholders.

[86] On 25 April 2007, Delta Two, a Qatari investment company, bought a 14% stake in Sainsbury's causing its share price to rise 7.17%, and then increased its holding to 17.6%.

[88] Paul Taylor, the principal of Delta Two, flew David and John Sainsbury to Sardinia to reveal and discuss the potential bid which amounted to 600p per share.

[90] On 5 November 2007, it was announced Delta Two had abandoned its takeover bid due to the "deterioration of credit markets" and concerns about funding the company's pension scheme.

[106] Throughout 2016 and 2017 Sainsbury's pursued expansion of its multi-channel strategy, increasing the number of groceries Click and Collect points and online fulfilment locations to serve its online delivery network including opening a dark store in Bromley by Bow to serve the London area, increasing geographical coverage of its same-day groceries delivery network and integrating concessions into its shops such as Argos, Habitat, Timpson's and Starbucks.

However depending on the size of the premises, they may also have an in-shop bakery, pizza counter, a cafe or Fresh Kitchen, Tu clothing, general merchandise with some stores having an on-site Argos and / or petrol station along with an online picking department.

The supermarket stated that the decision was an effort to reduce expenses in anticipation of a £140 million increase in costs resulting from upcoming budget tax measures set to take effect within weeks.

In 1996, on Monday 30 December it was announced that Sainsbury's has joined forces with Hewlett-Packard for the development of an Internet-based supermarket offering a full range of products.

[152] In October 2024, Sainsbury's announced the sale of its personal loans, credit Cards and savings business to National Westminster plc, with an expected completion by Q1 2025.

[170] In 2011, Sainsbury's opened a trial food to go shop in Fleet Street London selling sandwiches, baguettes and hot snacks in an effort to expand its business into new areas of opportunity.

[175] Sainsbury's Compare and Save was a comparison and switching service website that promoted a wide range of television, broadband and telephone deals from a variety of providers.

The flagship supermarket in Greenwich, South London, first trialled a modern "Sainsbury's" look, leading to the term 'Greenwich Blue', which was used to describe the signature colour of new identity.

The meetings can include communication from Head Office, the chance to organise charity or local events and the opportunity for employee's to discuss issues and feedback or question the attending Store Manager.

[246] Prior to 2005, Sainsbury's devised a scheme to avoid VAT by treating a 2.5% card transaction fee as exempt from the tax, although the total charged to the customer remained the same.

[247] In 2006, anti-poverty charity War on Want investigated the production of cut flowers to supermarkets, and criticised the conditions faced by workers at Sainsbury's Kenyan suppliers.

[253] Customers are held within a barriered area and must scan their printed receipt on an optical scanner to open an automatic gate, before they are permitted to exit the store.