Robert Michael James Gascoyne-Cecil was born on 30 September 1946 as the eldest child and first-born son of Robert Gascoyne-Cecil, 6th Marquess of Salisbury. His younger brother was the journalist Lord Richard Cecil, who was killed covering the conflict in Rhodesia in 1978.
Lord Cranborne attended Eton College and Christ Church, Oxford, and became a merchant banker before going to work on the family estates.
Lord Cranborne was selected, unexpectedly, as Conservative candidate for South Dorset in 1976, where his family owned lands, despite the presence of several former MPs on the shortlist. He spoke at the 1978 Conservative Party conference to oppose sanctions against Rhodesia. He won the seat in the 1979 general election, the seventh consecutive generation of his family to sit in the Commons, and in his first speech urged Ian Smith to stand aside in favour of Abel Muzorewa.
He attracted a general reputation as a right-winger, especially on matters affecting the Church of England, but confounded this reputation when he co-wrote a pamphlet in 1981 which said that the fight against unemployment ought to be given more priority than the fight against inflation. He took an interest in Northern Ireland, and, when Jim Prior announced his policy of 'Rolling Devolution', resigned an unpaid job as assistant to Douglas Hurd.
Lord Cranborne became known as an anti-communist through his activities in support of Afghan refugees in Pakistan in the early 1980s, and sending food parcels to Poland. Until the early years of the 21st century, a charity shop was run on his Hatfield estate solely to raise money for these causes, including funds for Polish orphanages. He was involved in efforts to fund the Afghan resistance. His strong opposition to any involvement by the Republic of Ireland in Northern Ireland led him to oppose the Anglo-Irish Agreement and contributed to his decision to retire from the House of Commons in 1987.
After the 1992 General Election, John Major used a writ of acceleration to call Lord Cranborne up to the House of Lords in one of his father's junior titles. Thus, Lord Cranborne was summoned to Parliament as Baron Cecil of Essendon (his father's most junior dignity), although he continued to be known by his courtesy style of Viscount Cranborne. This is the last time a writ of acceleration has been issued, and because of the provisions of the House of Lords Act of 1999, abolishing the automatic right of hereditary peers to sit in the House of Lords, any future use of the writ of acceleration is highly unlikely.
He served for two years as a junior defence minister before being appointed as Lord Privy Seal and Leader of the House of Lords in 1994. Funding for opposition parties in the House of Lords, known as Cranborne Money, began during his leadership. When Major resigned to fight for re-election as Conservative Party Leader in July 1995, Lord Cranborne led his re-election campaign. He was recognised as one of the few members of the Cabinet who were personally loyal to Major, but continued to lead the Conservative Peers after Labour won the 1997 General Election.
When the new Prime Minister Tony Blair proposed the removal of the hereditary element in the House of Lords, Lord Cranborne negotiated a pact with the government to retain a small number (later set at ninety-two) of hereditary peers for the interim period. For the sake of form this amendment was formally proposed by Lord Weatherill, Convenor of the Cross-Bench Peers. However, Lord Cranborne gave his party's approval without consulting the Leader, William Hague, who knew nothing and was embarrassed when Blair told him of it in the House of Commons. Hague then sacked Lord Cranborne, who accepted his error, saying that he had "rushed in, like an ill-trained spaniel".
All former Leaders of the House of Lords who were hereditary peers accepted Life Peerages to keep them in the House in 1999. Lord Cranborne, who had received the title Baron Gascoyne-Cecil, of Essendon in the County of Rutland, remained active on the backbenches until the House adopted new rules for declaration of financial interests which he believed were too onerous. He took 'Leave of Absence' on 1 November 2001. He was therefore out of the House when he succeeded his father as 7th Marquess on 11 July 2003.
In January 2010, Lord Salisbury and Owen Paterson hosted secret talks at Hatfield House, involving the Democratic Unionist Party, the Ulster Unionist Party and the Conservative Party. These talks prompted speculation that the Tories were attempting to create a pan-unionist front to limit Sinn Féin and the Social Democratic and Labour Party in the General Election of 2010.
In September 2012, Lord Salisbury, in his role as Chairman of the Thames Diamond Jubilee Foundation, was knighted by The Queen and became a Knight Commander of the Royal Victorian Order.
He retired from the House of Lords on 8 June 2017.
He is a Deputy Lieutenant of Hertfordshire and the current President of the Friends of the British Library.
In 1970, aged 23, he married Hannah Stirling, niece of Colonel Sir David Stirling (a co-founder of the SAS) and a descendant of the Lords Lovat, Scottish Catholic aristocrats. The marriage was initially opposed by his family, chiefly because Stirling was a Roman Catholic.
During the 1970s, Lord and Lady Cranborne had two sons and three daughters (including twins), of whom the two elder daughters are married. Until recently, they lived at Cranborne Manor, Dorset. The family seat is Hatfield House, once home to Queen Elizabeth I of England, which was given to the family by James I of England in exchange for the Cecil family house Theobalds. The Cecils are landowners in Dorset, Hertfordshire and London, and the 7th Marquess ranked 352nd in the Sunday Times Rich List 2017, with an estimated net worth of £335m (of which the paintings at Hatfield accounted for £150m).
The Marquess of Salisbury's heir is his elder son Robert Edward "Ned" William Gascoyne-Cecil, Viscount Cranborne (b. 1970). He was a page of honour to the Queen from 1983 to 1986. The heir is currently unmarried, though he does have an illegitimate daughter born in 2001. The younger son Lord James has married and fathered one son, Thomas Richard James (b 2009).1946–1972: The Hon Robert Gascoyne-Cecil
1972–1979: Viscount Cranborne
1979–1987: Viscount Cranborne MP
1987–1994: Viscount Cranborne DL
1994–2003: The Rt Hon Viscount Cranborne DL
2003–2012: The Most Hon The Marquess of Salisbury PC DL
2012–present: The Most Hon The Marquess of Salisbury KCVO PC DL