The first issue, published on 4 December 1791 by W.S. Bourne, was the world's first Sunday newspaper.
Believing that the paper would be a means of wealth, Bourne instead soon found himself facing debts of nearly £1,600. In 1794, Bourne attempted to sell The Observer to anti-government based groups in London. When this failed Bourne's brother (a wealthy businessman) made an offer to the government, which also refused to buy the paper but agreed to subsidise it in return for influence over its editorial content. As a result, the paper soon took a strong line against radicals such as Thomas Paine, Francis Burdett and Joseph Priestley.
In 1807, the brothers decided to relinquish editorial control, naming Lewis Doxat as the new editor. Seven years later, the brothers sold The Observer to William Innell Clement, a newspaper proprietor who already owned a number of publications. The paper continued to receive government subsidies during this period; in 1819, of the approximately 23,000 copies of the paper distributed weekly, approximately 10,000 were given away as "specimen copies", distributed by postmen who were paid to deliver them to "lawyers, doctors, and gentlemen of the town." Yet the paper began to demonstrate a more independent editorial stance, criticizing the authorities' handling of the events surrounding the Peterloo Massacre and defied an 1820 court order against publishing details of the trial of the Cato Street Conspirators who were alleged to have plotted to murder members of the Cabinet. The woodcut pictures published of the stable and hayloft where the conspirators were arrested reflected a new stage of illustrated journalism that the newspaper pioneered during this time.
Clement maintained ownership of The Observer until his death in 1852. During that time, the paper supported parliamentary reform, but opposed a broader franchise and the Chartist leadership. After Doxat retired in 1857, Clement's heirs sold the paper to Joseph Snowe, who also took over the editor's chair. Under Snowe, the paper adopted a more liberal political stance, supporting the North during the American Civil War and endorsing universal manhood suffrage in 1866. These positions contributed to a decline in circulation during this time.
In 1870 wealthy businessman Julius Beer bought the paper and appointed Edward Dicey as editor, whose efforts succeeded in reviving circulation. Though Beer's son Frederick became the owner upon Julius's death in 1880, he had little interest in the newspaper and was content to leave Dicey as editor until 1889. Henry Duff Traill took over the editorship after Dicey's departure, only to be replaced in 1891 by Frederick's wife, Rachel. Though circulation declined during her tenure, she remained as editor for thirteen years, combining it in 1893 with the editorship of The Sunday Times.
Upon Frederick's death in 1905, the paper was purchased by the newspaper magnate Lord Northcliffe. After maintaining the existing editorial leadership for a couple of years, in 1908 Northcliffe named J. L. Garvin as editor. Garvin quickly turned the paper into an organ of political influence, boosting circulation from 5,000 to 40,000 within a year of his arrival as a result. Yet the revival in the paper's fortunes masked growing political disagreements between Garvin and Northcliffe. These disagreements ultimately led Northcliffe to sell the paper to William Waldorf Astor in 1911, who transferred ownership to his son Waldorf four years later.
During this period, the Astors were content to leave the control of the paper in Garvin's hands. Under his editorship, The Observer pioneered the concept of the modern quality Sunday newspaper. Circulation reached 200,000 during the interwar years, a figure which Garvin fought to maintain even during the depths of the Great Depression. Politically the paper pursued an independent Tory stance, which eventually brought Garvin into conflict with Waldorf's more liberal son, David. Their conflict contributed to Garvin's departure as editor in 1942, after which the paper took the unusual step of declaring itself non-partisan.
Ownership passed to Waldorf's sons in 1948, with David taking over as editor. He remained in the position for 27 years, during which time he turned it into a trust-owned newspaper employing, among others, George Orwell, Paul Jennings and C. A. Lejeune. Under Astor's editorship the Observer became the first national newspaper to oppose the government's 1956 invasion of Suez, a move which cost it many readers. In 1977, the Astors sold the ailing newspaper to US oil giant Atlantic Richfield (now called ARCO) who sold it to Lonrho plc in 1981. Since June 1993, it has been part of the Guardian Media Group.
In 1990 Farzad Bazoft, a journalist for the Observer, was executed in Iraq on charges of spying. In 2003 the Observer interviewed the Iraqi colonel who had arrested and interrogated Barzoft. who was convinced that Barzoft was no spy.
On 27 February 2005 The Observer Blog was launched, making The Observer the first newspaper to purposely document its own internal decisions, as well as the first newspaper to podcast. The paper's regular columnists include Andrew Rawnsley and Nick Cohen.
In addition to the weekly Observer Magazine which is still present every Sunday, for several years each issue of The Observer came with a different free monthly magazine. These magazines had the titles Observer Sport Monthly, Observer Music Monthly, Observer Woman and Observer Food Monthly.
Content from The Observer is included in the Guardian Weekly for an international readership.
The Observer was announced as National Newspaper of the Year at the British Press Awards 2007.
Whitehall Editor Jo Revill had, as Health Editor, been named Medical Journalist of the Year in 2000 and 2006 by two different organisations, when she was Health Editor.
In early 2010, the paper was rejuvenated. An article on the paper's website previewing the new version stated that "The News section, which will incorporate Business and personal finance, will be home to a new section, Seven Days, offering a complete round-up of the previous week's main news from Britain and around the world, and will also focus on more analysis and comment."
After the paper was rejuvenated in early 2010, the main paper came with only a small number of supplements - Sport, The Observer Magazine, The New Review and The New York Times International Weekly. The International Weekly, an 8-page supplement of articles selected from The New York Times, has been distributed with the paper since 2007. Every four weeks the paper includes The Observer Food Monthly magazine.
Previously, the main paper had come with a vast range of supplements including Sport, Business & Media, Review, Escape (a travel supplement), The Observer Magazine and various special interest monthlies, such as Observer Food Monthly, Observer Women monthly, Observer Sport Monthly and The Observer Film Magazine.
The Observer and its sister newspaper The Guardian operate a visitor centre in London called The Newsroom. It contains their archives, including bound copies of old editions, a photographic library and other items such as diaries, letters and notebooks. This material may be consulted by members of the public. The Newsroom also mounts temporary exhibitions and runs an educational program for schools.
In November 2007 The Observer and The Guardian made their archives available over the internet via DigitalArchive. The current extent of the archives available are 1791 to 2000 for The Observer and 1821 to 2000 for The Guardian. These archives will eventually go up to 2003.