His collection, 40 years in the making, was considered to have been the second largest in the world held privately and to have numbered over 1.5 million specimens.

Joicey employed specialist entomologists including George Talbot to curate his collection and financed numerous expeditions throughout the world to obtain previously unknown varieties.

Joicey's obituary in The Entomologist described him as "undoubtedly the most lavish patron of Entomology, in so far as butterflies and moths are concerned, that this country has ever boasted".

[5][7][8] He was educated at Aysgarth School, Yorkshire, and Hertford College, Oxford,[9] and was an Associate Member of the Institute of Mining Engineers from 1891.

[a] Joicey's boyhood interest in insects was encouraged by his parents, and at the age of sixteen he put together a small collection of British and foreign butterflies.

Joicey's father, at one time a millionaire, had left over £700,000 (approximately equivalent to £87,500,000 in 2023) in his estate in 1912, but his will ensured that no money went directly to his son.

[35] He died of heart failure on 10 March 1932 at his home, The Hill, in Witley, Surrey, aged 61,[15][42][43] and was buried at Holy Trinity Church, Sunningdale.

[44] Joicey's estate was valued at £1,151 (approximately equivalent to £100,900 in 2023),[45] his collection and museum having been principally paid for and owned by his mother.

The formation of a large collection has its value, because without access to plenty of material studies can only be incomplete and results are often erroneous.

[1]: 3 [15] Joicey employed curators, including Alfred Noakes (from 1906)[49][50] and George Talbot (from 1915),[51] with a staff of assistants.

[6][52] Between 1913 and 1921 Joicey bought further collections: those of Ernst Suffert, c. 1913, Fritz Ludwig Otto Wichgraf, 1913, Col. Charles Swinhoe, 1916, Roland Trimen, 1917, Lt.-Col. C. G. Nurse, 1919, Hamilton Druce, 1919, Heinrich Riffarth, 1919, Henry John Elwes, 1920, and Paul Dognin, 1921.

[57] During his lifetime, Joicey "presented to the Nation" between 200,000 and 300,000 Lepidoptera specimens including about 75,000 to the Natural History Museum.

[15][58][59] Shortly after Joicey's death in 1932 the Hill Museum was closed and the property sold by his mother's executors.

[46] Joicey's obituary in The Entomologist stated that, The closing of the Hill Museum and the disbanding of its staff are events which will have serious repercussions throughout the ranks of lepidopterists in all parts of the world, and will definitely retard the advance of this science.

[6]: 144 Joicey's Hill Museum produced more than 190 research articles which were published in a range of scientific journals.

[15][47][61][62] A report in Nature stated that, During his life-time, the late J. J. Joicey probably did more to stimulate the study of butterflies and moths, especially those of Africa, than any other private individual in Great Britain.

[63]The majority of the papers are of a purely systematic nature, consisting of the description of new species or the revision of various genera; but there are several of principally faunistic interest, as, for example, the Catalogue of the Lepidoptera of Hainan.