Tim Sainsbury joined Sainsbury’s in 1956. In 1959 he became deputy to Fred Salisbury. He was appointed Director of Estates, Architects and Engineers in 1962. In this role he was in charge of converting all the remaining counter service shops to self-service, and modernising the earlier self-service shops. When the Company listed on the London Stock Exchange on 12 July 1973, as J Sainsbury plc, his family at the time kept control with an 85% stake. Whilst his cousin, David Sainsbury, inherited his father Robert Sainsbury's entire 18% shareholding, Tim Sainsbury had to split his father Alan Sainsbury's 18% stake with his brothers JD Sainsbury and Simon Sainsbury, and so they held 6% each. It is believed that Sir Robert Sainsbury gave David Sainsbury his entire shareholding so that David would have more votes at the table, considering John Davan Sainsbury, who became Chairman in 1969 on Sir Robert Sainsbury's retirement, had a forceful, autocratic style of leadership, whereas David was always more cautious. Tim Sainsbury stepped down from the board in 1983 to further pursue his career in politics. In 1992 his brother JD Sainsbury retired and was succeeded as chairman and chief executive by his cousin, David Sainsbury; this brought about a change in management style - David was more consensual and less hierarchical but not in strategy or in corporate beliefs about the company's place in the market. Tesco overtook Sainsbury's to become the UK's largest supermarket chain in 1995. As a result, it is believed that JD Sainsbury asked Tim to re-join Sainsbury's as a non-executive director in 1995 to support David. David stepped down in 1998 to pursue a career in politics, and in 1999, Tim stepped down as non-executive director, meaning no member of the Sainsbury family now works for the Company. At the time he vowed "to remain a major and committed shareholder." On 13 January 2006, the company was notified that Sir Timothy Sainsbury no longer has a notifiable interest in the company's issued share capital, such interest now being below 3%. His wife, who had held the other half of his 6% stake, dropped her interest in Sainsbury's below 3% the previous week. When Sainsbury's was the target for takeover bids during 2007, it is believed that Tim was close to his brother JD Sainsbury in that he was unwilling to sell his remaining stake at any price, wanting to keep the company independent, as opposed to being closer to his cousin David Sainsbury, who indicated he was willing to let the Sainsbury's board open its books for due diligence if someone offered him a price of 600 pence per share or more. As of August 2009, Tim Sainsbury together with his wife were still thought to own just under 3% of the retailer. The Sainsbury family as a whole control approximately 15% of Sainsbury's. In the Sunday Times Rich List 2008 his family fortune was estimated at £1.3 billion.
Sainsbury and his two brothers funded an extension to the National Gallery at a cost of around £50 million, which opened in 1991 as the Sainsbury Wing. He was Chairman of the Somerset House Trust from 1997 until 2002, and was president of a £25m campaign for Worcester College, Oxford. He was appointed as a trustee of the Victoria & Albert Museum on 17 December 2003 and was re-appointed on 17 December 2007. Tim Sainsbury is Chairman of the V&A's International Council, which aims to secure major donations for the FuturePlan.
Family
He has two daughters, Camilla and Jessica, and two sons, James and Alexander. Camilla was married until late 2015 to Shaun Woodward. Jessica is married to Peter Frankopan.
