He married Maria, the eldest daughter of the Norfolk banker Dawson Turner, in 1815, afterwards living in Halesworth for 11 years, where he established a herbarium that became renowned by botanists at the time.

He expanded the gardens at Kew, building new glasshouses, and establishing an arboretum and a museum of economic botany.

[2][3] He was an amateur botanist who collected succulent plants,[4] and was, according to his grandson Sir Joseph Dalton Hooker, "mainly a self-educated man and a fair German scholar".

[12][13] He visited the Norwich botanist Sir James Edward Smith to consult his Linnean collections.

Many other nondescripts have been taken by him and his brother, Mr. J. Hooker, and I name this insect after them, as a memorial of my sense of their ability and exertions in the service of my favourite department of natural history.

[18] When a young man, Hooker gained the patronage and friendship of some of most important naturalists in eastern England, including Smith, who had founded the Linnean Society of London in 1788 and owned Carl Linnaeus's collection of plants and books, the botanist and antiquarian Dawson Turner, and Joseph Banks.

He was found by friends and taken to Dawson Turner's house, where he was cared for until he recovered completely from the effects of the snake's bite.

[16] By 1807, Hooker had begun work as a supervising manager at a brewery at Halesworth, in partnership with Dawson Turner and Samuel Paget.

[22][23] Sharing a quarter of the company, he lived in the brewery house, which had a large garden and a greenhouse in which he grew orchids.

His first botanical expedition abroad—at the suggestion of the naturalist Sir Joseph Banks, who had made a previous visit in 1772—was to Iceland, in 1809.

[26] During his return voyage, the Margaret and Anne, in a dead calm, was discovered to be on fire, the result of sabotage which was afterwards found to have been planned by Danish prisoners.

[27] Banks later offered Hooker the use of his own papers, and with these materials, along with the surviving parts of his own journal, his good memory aided him to publish an account of the island, its inhabitants and flora: his A Journal of a Tour in Iceland (1809) was privately circulated in 1811 and published two years later.

[28][15] In 1810–11, he made extensive preparations, and sacrifices which proved financially serious, with a view to travelling to Ceylon, to accompany the newly-appointed governor, Sir Robert Brownrigg.

[10] In 1813, encouraged by Sir Joseph Banks, he considered travelling to Java, but was dissuaded from the idea by friends and family.

[32] In February 1820, Hooker was appointed as the regius professor of botany in the University of Glasgow,[33] taking over from the Scottish physician and botanist Robert Graham, and inheriting a small botanic garden that was underfunded and lacking in plants.

[34] In May he was received by the University and read his inaugural thesis in Latin, written by his father-in-law, Dawson Turner.

[35] He soon became popular as a lecturer, his style being both clear and eloquent, and people such as local army officers came to attend them.

His work on the botanic garden resulted in experts expressing the view that "Glasgow would not suffer by comparison with any other establishment in Europe".

The plant collections at Kew were first enlarged systematically by Francis Masson in 1771,[50] but had since the death of George III slowly declined.

[10] In April 1841 he was appointed as the Garden's first full time Director, on the resignation of William Townsend Aiton.

[51][10] Following his appointment as director, a position he had long wished for,[10] he wrote "I feel as if I were to begin life over again", in a letter to Dawson Turner.

[53] The curator of Kew Gardens during Hooker's period as Director was the experienced and knowledgeable botanist John Smith (1798–1888).

[55] In 1843 the Palm House, to a design by the architect Decimus Burton and the iron founder Richard Turner, was constructed at Kew.

[56][10] The gardens and glasshouses were opened daily to the visiting public, who were allowed to wander freely there for the first time.

[58] Hooker lived with his family at West Park, a large house in which he accommodated 13 rooms of books in his library, which was seen as a public institution by the world's botanical experts, who were never turned away.

[59] Among his visitors were Queen Victoria, her husband Prince Albert and their children; during 1865—the year Hooker died—the attendance had risen to 529,241.

[6][10] He was engaged on the Synopsis filicum with the botanist John Gilbert Baker when he contracted a throat infection then epidemic at Kew.

[10] This was succeeded by a new edition of William Curtis's Flora Londinensis, for which he wrote the descriptions (1817–1828); by a description of the Plantae cryptogamicae of Alexander von Humboldt and Aimé Bonpland; by the Muscologia, a very complete account of the mosses of Britain and Ireland, prepared in conjunction with Thomas Taylor and first published in 1818;[63] and by his Musci exotici (2 volumes, 1818–1820), devoted to new foreign mosses and other cryptogamic plants.

[64] With William Wilson he edited the exsiccata series Musci Americani; or, specimens of mosses, Jungermanniae, &c. collected by the late Thomas Drummond, in the Southern States of North America.