Johannes Carl Andersen was born on 14 March 1873 at Klakring, a village in Jutland, Denmark, the second child of Jørgen Andersen, a watchmaker, and his wife, Johanne Marie Hansen. The family arrived at Lyttelton, New Zealand, on the Gutenberg in October 1874. After a few months in the Oxford district in North Canterbury, the family settled in Christchurch. Johannes completed his schooling at Papanui School where he was dux in successive years. In March 1887 he was given a temporary job in the Christchurch office of the Department of Lands and Survey, where he continued to work as a cadet draughtsman and then clerk for nearly 28 years. In the 1890s Andersen was a champion gymnast and a tennis player, earned local distinction in chess, and enjoyed an active social life. He may have met Catherine Ann McHaffie, a teacher at Christchurch Normal School, at a dance; Kate and Jack Andersen (as they called each other) were married at Christchurch on 9 May 1900.
Andersen wrote much poetry, and in the later 1890s and early 1900s his verse appeared frequently in New Zealand newspapers and in the Sydney Bulletin. A first selection was published as Songs unsung (1903). Favouring artificial forms of verse (villanelles, rondels, and the like) then in vogue in England, he made an intensive study of prosody and corresponded with overseas scholars. The laws of verse, a fraction of his labours on these matters, was published (with a subsidy from a literary patron) by Cambridge University Press in 1928. He also tried his hand at translation, completing an English version of Adam Oehlenschläger's Danish epic Hrolf Krake, which was published in the Otago Witness.
Seeking local subjects for an epic of his own, Andersen turned to Māori mythology. Disheartened by the response to his original verse manuscript, he refashioned it as prose; Māori life in Ao-tea, a compendium of traditional lore drawn from printed sources, was published in 1907, and established him as a Pākehā authority on the Māori. In newspapers and in lectures, Andersen advised Pākehā artists and poets to 'leave the Greek and turn to the Māori' for their inspiration. His views aroused some interest, in part because he had become a minor antipodean laureate, winning an Australasian competition for an ode (set to music by Alfred Hill) to open the New Zealand International Exhibition held in Christchurch in 1906–7; and also because a number of contemporaries were similarly searching for local subjects which could be deployed to symbolise a specifically New Zealand identity.
Andersen began to make a close study of native flora and fauna, eventually producing a book, Bird-song and New Zealand song birds (1926), which presented the songs of birds in conventional musical notation. Extending the topographical knowledge he acquired in the Lands and Survey Department office, he sought to give the local landscape historical and personal colour by collecting Māori and Pākehā placenames, divining their meanings and establishing why and by whom they had been bestowed. A portion of his lifelong labours in this field later appeared as Place names of Banks Peninsula (1927); his growing literary reputation led to a commission to compile the mammoth Jubilee history of South Canterbury (1916).
The Andersens moved to Wellington in 1915 when Johannes was appointed an assistant in the General Assembly Library. The capital provided a congenial intellectual life, especially at meetings of the Wellington Philosophical Society where Andersen made contact with numerous amateur and professional scientists. One result was the editorship of the New Zealand Institute's Transactions, New Zealand's premier scientific journal, from 1920 to 1929; for these editorial exertions, and for learned papers on birdsong and prosody, he was elected a fellow of the New Zealand Institute in 1923. Another result was membership of four Dominion Museum ethnological expeditions between 1919 and 1923, Andersen's first and only substantial contacts with Māori communities. On these expeditions, to Gisborne, Rotorua, up the Whanganui River and to the East Cape district, in the company of Elsdon Best, James McDonald and (on the final two trips) Peter Buck, Andersen made recordings on wax cylinders of traditional Māori music and collected whai (string figures). As well as articles on these subjects, he published Māori string figures (1927), still a standard work, and Māori music with its Polynesian background (1934), in large measure a compilation of earlier observations.
Impressed by Andersen's energy and enthusiasm, Elsdon Best invited him to co-edit the Journal of the Polynesian Society in 1925. Andersen continued as editor after Best's death in 1931, defending the orthodox view of Polynesian traditional history established by Best and S. Percy Smith against the revisions proposed by H. D. Skinner (who resigned as joint editor of the Journal in 1934) and Roger Duff. Much assisted by finance from the Māori Purposes Fund Board (of which he was a member), Andersen by his efforts kept both the society and the Journal alive despite difficulties during the 1930s. His contribution to New Zealand anthropology was recognised by the award of the Hector Memorial Medal and Prize in 1944.
Although Andersen gained esteem through his association with the Polynesian Society, he was best known to the public as the first librarian of the Alexander Turnbull Library, the most significant New Zealand collection of manuscript and printed materials. Andersen took up this post in 1919, attempting over the next 18 years to turn what had been the private library of a Wellington merchant into a research institution. He augmented the stock, when governments proved parsimonious, by eliciting donations and bequests, especially the notable collection of Sir Joseph Kinsey of Christchurch. Visitors, adults and children alike, were shown the library's 'treasures' – manuscripts and rare editions – and Andersen publicised the library in articles and through innumerable lectures he gave in many parts of Wellington province and sometimes further afield.
Andersen was a popular speaker and broadcaster on a wide range of topics. At schools, in halls, and at teachers' summer schools (where he relished contact with young women teachers) he shared his enthusiasm for verse, native flora and fauna, Māori culture, New Zealand history, Māori and Pākehā placenames, and Polynesian myths and legends. Above medium height (though his back became hunched as he aged), with hair longer than was customary, and piercing eyes in a face more fierce-looking than handsome, he aroused the attention of listeners with a gentle, anecdotal style of speaking. His pièce de résistance was his mimicking of bird songs by whistling: audiences never seemed to tire of this performance, and Andersen always enjoyed the applause.
Many of those who did not hear Andersen speak were likely to have read some of his words. He published nearly 30 books and booklets, including six solid volumes between 1926 and 1928, among them New Zealand tales and translations from the Danish (1927), a collection of his unpublished and previously published fiction, and Myths & legends of the Polynesians (1928), commissioned by the London publisher George Harrap. In addition, he wrote frequently to newspapers, particularly about the need to protect native flora and fauna, and about placenames. He was appointed in 1924 to the Honorary Geographic Board of New Zealand, in the formation of which he played a major part, and was its most active member in recommending correct forms of placenames. He was a keen collector of books for himself as well as the Turnbull Library, and reported the thrill of the chase in The lure of New Zealand book collecting (1936).
When Andersen escaped the thrall of books, he enjoyed the company of bush and birds, especially during holidays on Kapiti Island. A little house set amidst regenerated bush at Point Howard, on Wellington Harbour, purchased in the early 1930s, suitably reconciled study and the outdoors. Kate was less rhapsodic about the wilderness. She was prominent in many welfare and women's organisations, and her standing was recognised by her appointment as a justice of the peace in 1935. For his various services, Johannes was appointed an MBE the same year. One of his rewards which they both shared was a journey in 1936 to Britain, with a few days in Denmark, and attendance at the PEN literary conference in Buenos Aires. Johannes felt homesick for New Zealand at times; Kate, short and stout, found it difficult to keep her dignity when they crossed a high mountain pass in the Andes on horseback.
Reluctant retirement from the Turnbull Library in 1937 still left Andersen very busy: besides articles, lectures and broadcasts, Polynesian Society affairs and research for further books (his massive 'preliminary essay' on Māori place-names appeared in 1942), he was an active president of both the New Zealand Ex Libris Society and the New Zealand Numismatic Society, and was on the committee of management of the Dominion Museum. During the war he reasserted his Danish heritage. He helped to collect patriotic funds for the Danish Association in New Zealand and, after there was a disagreement in that organisation (which he helped to precipitate), was founder and president of the breakaway N.Z. Anglo-Danish Society; in 1948 he was made a Knight of Dannebrog by the King of Denmark.
Andersen persuaded Sir Apirana Ngata, in the early 1940s, to begin rendering the classic corpus of Māori songs, Ngā mōteatea, into English. Ngata was more concerned to record the Māori words of traditional songs and was inclined to regard translation as a distraction. Only in translation would Andersen, whose understanding of the Māori language was limited, have access to this cultural 'mine of wealth'. He sent copies of his translated Songs for the N.Z. Anglo-Danish Society (1944) and his small annotated bilingual collection of Polynesian literature: Māori poetry (waiata and tangi) (1946) to Ngata; but these spurs, together with Andersen's editorial interventions, may have annoyed rather than encouraged Ngata. When Kate found the steep paths of Point Howard too much for her health, and the Andersens decided to move to Auckland in 1946, members of the Polynesian Society council gained Ngata's support for a decision to relieve Johannes of the editorship of the Journal.
In Auckland, living first at Laingholm and later at Mount Eden, Johannes continued to give occasional lectures, and added further publications: two booklets on insects; The Māori tohunga and his spirit world (1948); a personal memoir of Old Christchurch in picture and story (1949), arranged around A. C. Barker's photographs; a fifth volume of verse, The tui-cymbalist and other verses (1951); and, finally, The Mair family (1956), co-authored with G. C. Petersen. By the later 1950s plans for further books and his journeys to Wellington to attend meetings of the New Zealand Geographic Board and Māori Purposes Fund Board were curtailed by physical enfeeblement. Kate had died in 1957; Johannes lived with his younger son and his daughter-in-law at Kohimarama, eventually dying at Mount Albert on 19 June 1962, survived by two sons.
A later generation of cultural high priests was critical of Andersen for his dilettantish librarianship, the banality of his verse and his pedantry, but these are aesthetic rather than historical judgements about his cultural significance. The Danish-born Andersen found Anglo-colonial culture lacking in resonance, but since his Danish heritage had been attenuated by early migration, he felt more acutely than most the usual difficulties of constructing an identity in a settler society. In a similar fashion to several contemporaries, but more self-consciously, deliberately and persistently than others, he fabricated an identity out of indigenous phenomena, especially celebration of the bush, the birds and the Māori, and disseminated his attitudes to a receptive wider community through a variety of media. Although antagonistic to the depredations of the early colonists, he was himself a coloniser, appropriating aspects of Māori culture for his own purposes while never, for all his sympathy with Māori, becoming bicultural. The cultural legacies of Andersen and of others who followed similar imperatives continue to be both pervasive and problematic.