Herbert William Williams was born at Waerenga-a-hika, near Gisborne, New Zealand, on 10 October 1860. The son of the third bishop of Waiapu, William Leonard Williams, and his wife, Sarah Wanklyn, he was also grandson of the first bishop of Waiapu, William Williams. Herbert was educated at Christ's College, Christchurch, from 1874 to 1878 and at Canterbury College, where he graduated BA in 1880. He then went to the University of Cambridge where, at Jesus College, he was a Rustat scholar. A keen rugby player, he captained the Jesus College XV. He graduated BA in 1884 and MA in 1887, and was ordained priest the same year.
On 27 September 1888 at Edinburgh Herbert Williams married Bertha Louise Gertrude Mason. He taught for two years at Haileybury College, Hertfordshire, and in 1889 returned to New Zealand as vice principal of Te Rau Theological College, Gisborne, which had been opened in 1883 as a training centre for Maori clergy. He became principal in 1894 but was forced by throat trouble to retire in 1902. That year he devoted his time to superintending Maori mission work, often travelling with his father to all parts of the Waiapu diocese.
In 1907 he was appointed archdeacon of Waiapu. He strove to improve the finances in order to further the promotion of the church among Maori, many of whom had turned to messianic cults or reverted to beliefs in old gods. More local funding was particularly urgent because the Church Missionary Society in England was about to cease making contributions from their own funds and leave the church in New Zealand to take up full responsibility for the work of the Maori mission.
In December 1928 a Maori, F. A. Bennett, was consecrated as suffragan bishop to the Waiapu diocese with the title Bishop of Aotearoa; Archdeacon Williams preached the sermon. A few months later Williams was elected bishop of Waiapu to succeed W. W. Sedgwick. He was consecrated on 9 February 1930. Although he, like his father and grandfather, was esteemed by the Maori people, to whom he gave sympathy, counsel and guidance, he served under very different conditions.
His father and grandfather had both spent much of their time in difficult travel among the Maori population in remote areas of the diocese, but Herbert Williams's difficulties were of a different order. The 1930s were financially trying times for the church: in the early 1930s the depression deepened and in 1931 the Hawke's Bay earthquake destroyed St John's cathedral in Napier and destroyed or damaged churches and vicarages throughout the southern part of the diocese. While Williams is said not to have been an inspiring preacher, he was an able administrator who carried his diocese through this difficult period.
However, Herbert will be best remembered for his scholarship in the field of Maori language. His grandfather, William, had published the first substantial Maori-to-English dictionary in 1844. Enlarged editions, edited by Leonard, appeared in 1871 and 1892. For 15 years Herbert worked on a further revision. In January 1906 he had the opportunity of examining the collection of Maori manuscripts deposited in the South African Public Library at Cape Town by Sir George Grey (and he was responsible for their eventual return to New Zealand). Finally, in 1917, the greatly enlarged fifth edition of A dictionary of the Maori language was published under the auspices of the Polynesian Society by the Government Printer. This meticulously edited enhancement of earlier editions established the dictionary as the unsurpassed record of a Polynesian language, and Williams as the major Maori linguist of his day. It earned him honorary doctorates in literature from the Universities of New Zealand (1924) and Cambridge (1925).
In 1923 Williams published his revision of First lessons in Maori; previous editions, like the Dictionary, had been the product of his grandfather and father. This little book remained the standard treatment of the structure of Maori for many years. In 1924 he published A bibliography of printed Maori to 1900, in which more than 1,000 items are described.
Williams and Apirana Ngata campaigned for the recognition of Maori language as a subject for study in the University of New Zealand and it was finally listed for the degree of bachelor of arts in 1928. Williams had responded to the criticism that there was no original Maori literature by editing a new edition of the Maori text of George Grey's Polynesian mythology. This book, Nga mahi a nga tupuna (1928), and Ngata's collection of song texts, Nga moteatea (1928) remain the most important collections of Maori traditional literature.
Williams was president of the Royal Society of New Zealand (1935–36), and of the Polynesian Society from 1929 until his death. He wrote a number of articles on Maori language and culture for the Polynesian Society's journal. His position regarding the various ethno-historical theories on Maori traditions and origins was essentially conservative. He anticipated modern scholarship in questioning the antiquity of the belief that Io was a supreme god of the Maori pantheon, and in suggesting that there was a Melanesian component among the Maori forebears. With regard to Maori origins he considered that we should be satisfied not to know clearly just what happened a thousand years ago.
While still serving as bishop of Waiapu, and after almost 50 years service to the Maori mission of the Anglican church, H. W. Williams died suddenly in Napier on 6 December 1937. He was survived by his wife, four sons and three daughters.