William John Burchell was born in Fulham on 23 July 1781 to Matthew Burchell. He was educated at Raleigh House Academy in Surrey and worked at Kew Gardens, becoming a fellow of the Linnean Society in 1803. In 1805 he arrived on St Helena, 1,200 miles (1,950km) from the south-west coast of Africa. In September 1806 he became the island's schoolmaster and in November of the same year he was also appointed superintendent of the botanic garden. He experimented with seeds and plants from South America, Africa and the Far East brought by ships to the island and he also studied the island's botany and geology. In 1808 gave up the job of schoolmaster after he was appointed the role of naturalist on the island and it became his responsibility to survey the island's natural resources.
Burchell was invited to become a botanist in Cape Colony in South Africa and in November 1810 he arrived in Cape Town and travelled locally for seven months. In June 1811 he set off on a major exhibition into Cape Colony and Bechuanaland which lasted four years and covered 4500 miles. He arrived back in England on 11 November 1815.
Burchell brought to England some 63,000 specimens of plants, seeds, insects, fish and animal skins and skeletons, which he had collected on his travels. This has been described as the largest collection made by one man ever to leave Africa. He had also made 500 field sketches and botanical, zoological and ethnographic drawings and kept detailed notes of his travels and observations of natural history. Between 1815 and 1819 he classified his specimens and cultivated the seeds and bulbs he had collected. In 1819 he began to work on his Travels in the Interior of Southern Africa. The two volumes published (1822 and 1824) cover his journeys to August 1812, but a projected third volume never appeared.
In 1825 Burchell joined a British diplomatic mission to Brazil. Travelling via Lisbon, Madeira and the Canary Islands he arrived in Rio de Janeiro in July. He spent thirteen months collecting botanical, zoological and geological specimens in the vicinity of the city, Serra dos Órgãos, and in southern Minas Gerais. In September 1826 he sailed to Santos and collected in the Cubatão area, before moving to São Paulo in January 1827. In July 1827 he travelled north across São Paulo province and the Triangûlo Mineiro into Goiás, claiming to be the first Englishman to visit it. He spent nine months in the town of Goiás and then, between August and November 1828, journeyed to Pôrto Real where he waited five months until water conditions allowed him to sail 690 miles down the River Tocantins to the Amazon. He arrived in Belém on 10 June 1829 and only then did he learn that his father had died in July 1828. Burchell remained in Belém until February 1830 and arrived back in England on 24 March of that year.
Burchell spent the remaining three decades of his life in the labour of cataloguing his enormous collections. He has been described as a sensitive perfectionist, and his meticulousness meant that, working alone, this was a slow process. His material from Brazil, which totalled over 52,000 specimens, was not catalogued until 1860. Burchell received little public recognition for his work. However he was appointed to the council of the British Association for the Advancement of Science in 1832, and awarded an honorary DCL by Oxford University in May 1834. A number of St Helena and South African plants, animals and birds are named after him.
Burchell progressively withdrew from his scientific friends and on 23 March 1863 he committed suicide at the family home in Fulham.