Hunt, a British Army Colonel, was serving on the staff at Supreme Headquarters Allied Powers Europe when to his surprise he was invited by the Joint Himalayan Committee of the Alpine Club and the Royal Geographical Society to lead the British Everest expedition of 1953. Eric Shipton had been widely expected to be the leader, because he had led the Mount Everest reconnaissance expedition from Nepal in 1951 as well as the unsuccessful British attempt on Cho Oyu in 1952, from which expedition most of the climbers selected had been drawn. However, the Committee had decided that Hunt's experience of military leadership, together with his credentials as a climber, would provide the best prospect of success. The British felt under particular pressure, as the French had received permission to mount a similar expedition in 1954, and the Swiss another in 1955, meaning that the British would not have another chance at Everest until 1956 or later. As Shipton wrote in a statement of his position presented to the Committee on 28 July 1952: "My well-known dislike of large expeditions and my abhorrence of a competitive element in mountaineering might well seem out of place in the present situation." This statement, according to George Band, "sealed his own fate".
Several members of the British expedition had a strong loyalty to Shipton and were unhappy that he had been replaced. Charles Evans, for instance, stated: "It was said that Shipton lacked the killer instinct – not a bad thing to lack in my view." Edmund Hillary was among those most opposed to the change, but he was won over by Hunt's personality and by his admission that the change had been badly handled. George Band recalls Committee member Larry Kirwan, the Director/Secretary of the Royal Geographical Society, saying that "they had made the right decision but in the worst possible way".
Hunt later wrote that the Joint Himalayan Committee had found the task of raising funds for the expedition challenging:
One of the principal tasks of the Joint Himalayan Committee in addition to those of conceiving the idea of an Everest expedition, seeking political sanction, deciding matters of policy in preparation, is to finance it. Only those who have had this care can fully appreciate the work and anxiety of raising very substantial funds for an enterprise of this nature, coloured as it inevitably is in the mind of the public by a succession of failures, with no financial security other than the pockets of the Committee members themselves.
The party departed for Nepal from Tilbury, Essex, England aboard the S.S. Stratheden bound for Bombay on 12 February, bar Tom Bourdillon, Dr Griffith Pugh, and Hunt, who was ill with an antrum infection. Evans and Alfred Gregory had flown on ahead to Kathmandu on 20 February, as the Advance Party. Hillary and Lowe approached Nepal from New Zealand, Lowe by sea and Hillary by air, as his "bees were in a busy state at that time of year". Although a sea passage was cheaper, Hunt stated that the main reason for choosing it over an air journey was "the further chance which life in a ship would provide for us to settle down as a team in ideal conditions, accompanied by no discomfort, urgency or stress".
In Kathmandu, the party was looked after by the British ambassador, Christopher Summerhayes, who, in Band's words, "arranged billets for us all with the various Embassy staff", there being no hotels in Kathmandu at the time. In early March twenty Sherpas, who had been chosen by the Himalayan Club, arrived in Kathmandu to help carry loads to the Western Cwm and the South Col. They were led by their Sirdar, Tenzing Norgay, who was attempting Everest for the sixth time and was, according to Band, "the best-known Sherpa climber and a mountaineer of world standing". Although Tenzing was offered a bed in the embassy, the remaining Sherpas were expected to sleep on the floor of the embassy garage; they urinated in front of the embassy the following day in protest at the lack of respect they had been shown. The first party, together with 150 porters, left Kathmandu for Mount Everest on 10 March, followed by the second party and 200 porters on 11 March. They reached Thyangboche on 26 and 27 March respectively, and between 26 March and 17 April engaged in altitude acclimatization.
The "Icefall party" reached Base Camp at 17,900 feet on 12 April 1953. A few days were then taken up, as planned, in establishing a route through the Khumbu Icefall, and once this had been opened teams of Sherpas moved tonnes of supplies up to Base.
A series of advanced camps were created, slowly reaching higher up the mountain. Camp II at 19,400 feet was established by Hillary, Band and Lowe on 15 April, Camp III at the head of the Icefall at 20,200 feet on 22 April, and Camp IV by Hunt, Bourdillon and Evans on 1 May. These three made a preliminary reconnaissance of the Lhotse Face on 2 May, and Camp V at 22,000 feet was established on 3 May. On 4 May, Bourdillon and Evans, supported by Ward and Wylie, reached Camp VI at 23,000 feet on the Lhotse Face, and just under a fortnight later on 17 May, Wilfrid Noyce and Lowe established Camp VII at 24,000 feet. By 21 May, Noyce and the Sherpa Annullu (the younger brother of Da Tenzing) had reached the South Col, just under 26,000 feet. The first of two climbing pairs previously selected by Hunt, Tom Bourdillon and Charles Evans, set out for the summit on 26 May using closed-circuit oxygen and successfully achieved the first ascent of the 8,750 m (28,700 ft) South Summit, coming within 100 m (300 ft) of the final summit. They were forced to turn back after becoming exhausted, defeated by oxygen equipment problems and lack of time. On 27 May, the expedition made its second and final assault on the summit with the second climbing pair, the New Zealander Edmund Hillary and Sherpa Tenzing Norgay from Nepal. Norgay had previously ascended to a record high point on Everest as a member of the Swiss expedition of 1952. They reached the summit at 11:30 am on 29 May 1953, climbing the South Col route. Before descending, they stopped at the summit long enough to take photographs and to bury some sweets and a small cross in the snow.
Well, George, we knocked the bastard off.
James Morris, the correspondent on the spot of The Times newspaper, heard the news at Base Camp on 30 May and sent a coded message by runner to Namche Bazaar, where a wireless transmitter was used to forward it as a telegram to the British Embassy in Kathmandu. The conquest of Everest was probably the last major news item to be delivered to the world by runner. Morris' encoded message to his paper read: "Snow conditions bad stop advanced base abandoned yesterday stop awaiting improvement". "Snow Conditions Bad" was the agreed code to signify that the summit had been reached, while "Advance Base Abandoned" referred to Hillary (Evans's phrase was "Ridge Camp Untenable" and Westmacott's "Assault Postponed"). This was received and understood in London in time for the news to be released, by happy coincidence, on the morning of Queen Elizabeth II's coronation on 2 June.
Returning to Kathmandu a few days later, the expedition learned that Hillary had already been appointed a Knight Commander of the Order of British Empire and Hunt a Knight Bachelor for their efforts. On 22 June, the Government of Nepal gave a reception for the members of the expedition at which the senior queen of the country presented Tenzing with a purse of ten thousand rupees, which was then about £500. Hillary and Hunt were given kukris in jewelled sheaths, while the other members received jewelled caskets. The same day, the Government of India announced the creation of a new Gold Medal, an award for civilian gallantry modelled on the George Medal, of which Hunt, Hillary and Tenzing would be the first recipients. On 7 June it was announced that Queen Elizabeth II wished to recognize the achievement of Tenzing, and on 1 July, 10 Downing Street announced that following consultation with the governments of India and Nepal the Queen had approved the award of the George Medal to him. Some commentators have seen this lesser honour as a reflection of the "petty bigotry" of the British establishment at the time, although it has been suggested that the Indian prime minister, Jawaharlal Nehru, refused permission for Norgay to be knighted. Hunt received his knighthood in July 1953, on his return to London.
Further honours continued to descend on the members of the expedition: the Hubbard Medal of the National Geographic Society, which had never before been awarded on a team basis, although individual medals were struck in bronze for Hunt, Hillary and Tenzing; the Cullum Geographical Medal of the American Geographical Society, the Founder's Medal of the Royal Geographical Society; the Lawrence Medal of the Royal Central Asian Society; and honorary degrees from the universities of Aberdeen, Durham, and London. In the New Year Honours list of 1954, George Lowe was appointed a Commander of the Order of the British Empire for his membership of the expedition.
The expedition's cameraman, Tom Stobart, produced a film called The Conquest of Everest, which appeared later in 1953.
Although Hillary and Tenzing represented their triumph as belonging to a team effort by the whole of the expedition, there was intense speculation as to which of the two men had actually been first to set foot on the summit of Everest. In Kathmandu, a large banner depicted Tenzing pulling a "semi-conscious" Hillary to the summit. Tenzing eventually ended the speculation by revealing that Hillary had been first to the summit. After this Hillary himself wrote that following his ascent of the 40-foot Hillary Step, lying just below the summit:
I continued on, cutting steadily and surmounting bump after bump and cornice after cornice looking eagerly for the summit. It seemed impossible to pick it and time was running out. Finally I cut around the back of an extra large lump and then on a tight rope from Tenzing I climbed up a gentle snow ridge to its top. Immediately it was obvious that we had reached our objective. It was 11.30 a.m. and we were on top of Everest!
Shipton commented on the successful ascent: "Thank goodness. Now we can get on with some proper climbing."
The expedition participants were selected for their mountaineering qualifications and also for their expertise in providing a number of other necessary skills and support services. Griffith Pugh's impact is often overlooked. He improved activities such as hydration and oxygen intake, and enabled sustained mountaineering efforts. His ideas revolutionised almost every aspect of British high-altitude mountaineering, transforming the climbers' attitude to oxygen, the clothes they wore, their equipment, fluid intake and acclimatisation. While most were from the United Kingdom itself, they were also drawn from other countries of the British Empire and Commonwealth of Nations. The leader, Hunt, had been born in India.
The mountaineers were accompanied by Jan Morris (known at the time under the name of James Morris), the correspondent of The Times newspaper of London, and by 362 porters, so that the expedition in the end amounted to over four hundred men, including twenty Sherpa guides from Tibet and Nepal, with a total weight of ten thousand pounds of baggage.