Leslie George Kelly was born in Auckland on 10 May 1906, the elder of two sons of Sidney Mellish Kelly, a french polisher, and his wife, Ethel May Fell. On his father’s side Kelly was descended from Edward Meurant, a trader and interpreter at Kāwhia in the 1830s, and his wife, Kenehuru, the daughter of Ngāti Mahuta leader Te Tuhi-o-te-rangi.
Kelly was educated at Beresford Street School and Mount Albert Grammar School. In his teens he was a keen member of the Grey Lynn boy scouts, collecting many badges and awards. He was also an accomplished photographer with numerous photographs in family albums attesting to his skill and patience in colour tinting. In the early 1920s he was a junior reporter for one of the daily newspapers in Auckland.
Kelly joined the Railway Department in 1926, eventually working his way up from fireman to first-class engine-driver. On 11 February 1929, in Auckland, he married Heera (Sarah) Te Moengaroa Ueke, who was of Ngāi Tāwake (a hapū of Ngāpuhi) and Ngāti Mahuta. They had two sons and a daughter.
During his time with the railways Kelly was stationed at a number of Waikato and King Country towns, especially Te Kūiti, where he made many toys for his children and grandchildren. He also constructed a fully working model railway and was well known for his prowess as an artist and carver. Using only rudimentary tools such as a pocketknife and tomahawk, he produced many fine carved hand weapons (taiaha, tewhatewha, patu, mere) and wakahuia (carved boxes).
By the late 1920s Kelly was researching tribal history and collecting whakapapa, beginning with his wife’s Ngāpuhi connections. He frequently met and corresponded with Māori and Pākehā informants; one of these was his relative, Hāmi Maioha, of the Bay of Islands. Another was the journalist Eric Ramsden.
Kelly’s sister-in-law, Aira (Ida) Totorewa Stewart (née Ueke), accompanied him on many of his trips and later helped him with the translation of old waiata. His research work, done by necessity at weekends and during holidays, took him all over Waikato, the King Country, the Bay of Islands and Taranaki. He talked with a great many old Māori people, and with their permission recorded their whakapapa, kōrero and waiata. During the 1950s he visited Rarotonga and Niue to research the original Māori canoe voyages. Kelly was a prolific diarist, keeping notes on his frequent travels or people he met or interviewed.
By 1931 he had begun to publish his findings in the Journal of the Polynesian Society; 18 of his papers had appeared in that journal by 1955. In 1934 he published two articles on Marion du Fresne in the New Zealand Herald, and in 1951 he published Marion Dufresne at the Bay of Islands.
In 1935 Kelly met Te Puea Hērangi. She researched his ancestry and by 1939 had chosen from his whakapapa the ancestral name Te Putu, also an ancestor of the Māori Kings. This was the period he researched and wrote his history of Tainui, initially collaborating with Pei Te Hurinui Jones. Kelly sent a version of the manuscript to Apirana Ngata, who refused to recommend it to either the Māori Purposes Fund Board or the Polynesian Society; he found it disappointing, considering that it concentrated too much on dates and battles and too little on the growth and development of the Tainui tribes. Nevertheless, he told Kelly that the board would publish a revised manuscript.
Tainui, Kelly’s major work, was eventually published as a Polynesian Society memoir in 1949. It was later alleged that Kelly had tricked Te Puea into endorsing the book in her foreword, and that he had plagiarised the whole book from work by Pei Te Hurinui Jones. Pei had intended to publish a similar work himself, and, as a close relative of the kāhui ariki (royal family), probably believed he had a greater right. He felt insufficiently acknowledged: while his accounts were cited by Kelly in the text, his manuscripts were not included in the list of sources.
Kelly had made no secret of his work, having been in correspondence with Ngata and others about it since 1937, and it is doubtful that he had any notion that what he was doing could be considered plagiarism. Certainly, parts of Tainui made extensive use of Pei's collection, and permission to use material may not have been formally sought. But the wording is rarely exactly the same, and Kelly acknowledged Pei in the text alongside all his other sources. Internal evidence in the book, as well as his correspondence, confirms that Kelly also did research of his own; Pei Jones cited Tainui in his notes to the revised edition of Ngā mōteatea in 1958.
Kelly was intensely passionate, totally dedicated, meticulous about detail and a perfectionist in everything he did. Extremely talented, he expected everyone else – including his family – to meet his high standards and to share his own passion for things Māori. He was killed in a train crash at Motumaoho, Morrinsville, on 6 August 1959, and was survived by his wife and children.