Born in 1948, Davis was raised on a council estate in South London. After a grammar school education, he went on to gain a Master's degree in business at age 25, and went into a career with Tate & Lyle.
Upon entering Parliament in 1987 at age 37 for the Boothferry constituency, in his subsequent political career he held the positions of Conservative party chairman and Shadow Deputy Prime Minister. Since 2003 he had been the Shadow Home Secretary in the shadow cabinet, under both Michael Howard and David Cameron. Davis had previously been a candidate for the leadership of the Conservative Party in 2001 and 2005, coming fourth and then second.
On 12 June 2008, in a surprise and controversial move, Davis announced his intention to resign as an MP, and was immediately replaced as Shadow Home Secretary. This was in order to force a by-election in his seat, for which he intended to seek re-election by mounting a specific campaign designed to provoke wider public debate about the perceived erosion of civil liberties in the United Kingdom. Following his formal resignation as an MP on 18 June 2008, he officially became the Conservative candidate in the resulting by-election and won it on 10 July 2008.
On leaving Bec Grammar School in Tooting, his 'A' Level results were not good enough to secure a university place. Davis worked as an insurance clerk and became a member of the Territorial Army's 21 SAS Regiment in order to earn the money to retake his examinations. On doing so he won a place at the University of Warwick (BSc Joint Hons Molecular Science/Computer Science 1968-1971). Whilst at Warwick, he was one of the founding members of the Student Radio station, University Radio Warwick.
In 1999 Davis presented the Parliamentary Control of the Executive Bill to the House of Commons, in which he proposed to transfer ministerial exercise of the Royal Prerogative to the Commons in the following areas: the signing of treaties, the diplomatic recognition of foreign governments; European Union legislation; the appointment of ministers, peers and ambassadors; the establishment of Royal Commissions; the proclamation of Orders-in-Council unless subject to resolutions of the Commons; the exercise of the powers of the executive not made by statute; the declarations of states of emergency; the dissolution of Parliament.
In the following parliament, Davis held the position of Chairman of the House of Commons Public Accounts Committee between 1997 and 2001. In this role he began to build a reputation, and some Conservatives started to mention him as being a potential future leader of the Conservative Party.
Following the resignation of William Hague, he contested the 2001 election for the leadership of the Conservative Party, finishing fourth and being appointed Chairman of the Conservative Party by the eventual winner, Iain Duncan Smith. His most notable action in this post was the suspension of the Monday Club's affiliation with the Conservative Party because of its perceived inflammatory views on race.
In 2002, Duncan Smith replaced Davis with Theresa May. Davis was on a family holiday in Florida at the time and the manner of his sacking ensured a significant amount of sympathy among Conservative Party members. His new position was to shadow the Deputy Prime Minister John Prescott as Shadow Secretary of State for the Office of the Deputy Prime Minister. This was largely viewed as a demotion. When Duncan Smith was removed as Conservative leader by a vote of no confidence, Davis surprised commentators by quickly announcing that he would not stand for the leadership. He lent his support to Michael Howard who was not challenged allowing an uncontested election to take place. He was rewarded for this with a new role as Shadow Home Secretary.
In the role of Shadow Home Secretary, he successfully gained the 'scalp' of the then Immigration Minister Beverley Hughes, who was forced to resign in the wake of allegations that checks on Eastern European migrants had been waived, and for misleading the House of Commons. Davis was praised for his role in holding her to account at that time.
More recently Davis has turned the Conservatives away from the Labour Party's plan to reintroduce identity cards citing spiralling costs and libertarian issues. He turned initial Conservative support into one of concern and abstention, making the final change to one of opposition much easier. Davis believes that once the true cost and unreliability of the ID card scheme is explained to the general public, they will turn against it. Davis had maintained the Conservative's pledge to curb the moral degradation that he and other front benchers have declared part and parcel of "Blair's Britain".
Davis is perceived to be socially conservative. He expressed support for the restoration of the death penalty as recently as November 2003. He is highly sceptical of the political expansion of the European Union, voted against the repeal of Section 28 - a law banning promotion of homosexual relationships in schools - and voted against equalising the age of homosexual consent. However, he has consistently attracted support on a personal level from all sections of the party. Thus, when the gay Conservative MP Michael Brown was pictured on holiday with a 20-year-old man in 1994 (when the age of consent was still 21), Davis drove to Brown's home to offer his help.
At the 2005 General Election, he was targeted by the Liberal Democrats as part of their "decapitation plan", an attempt to undermine the Conservatives in Parliament by defeating their leading members. The targeting failed as Davis trebled his majority to over 5,000 votes (5,116, up from 1,903), his share of the votes increasing by 4.3%.
In the first ballot of Conservative MPs on 18 October 2005, Davis came top with 62 votes. As this was less than the number of his declared supporters, it became clear that the Davis bid was losing momentum. The elimination of former Chancellor Kenneth Clarke left the bookmakers' favourite, David Cameron, without a rival on the centre of the party. In the second ballot, held two days later on 20 October 2005, Cameron polled 90 votes, David Davis 57 votes and Liam Fox was eliminated with 51 votes so David Davis went through to the next stage with David Cameron.
In spite of a strong performance in a BBC Question Time head-to-head debate in the final stage of the leadership contest, Davis could not match his rival's general popularity. Conservative party members voted to elect Cameron the new Conservative leader, Davis losing by a margin of 64,398 votes to 134,446 votes. Cameron chose to re-appoint his rival as Shadow Home Secretary following his victory.