Henry James Fletcher was born at Denton, near Rochester, Kent, England, on 28 February 1868, the son of William Fletcher, a journeyman carpenter, and his wife, Jane Sally Fawcett. Henry was the fourth son of a family of five boys and four girls. In 1874 the Fletchers emigrated to New Zealand to take up land near Feilding. The section allotted to them was covered in standing timber, so William Fletcher purchased a town section in Bulls where the family settled. Henry and the rest of the family attended the Bulls school.
On leaving school at the age of 13 Henry was apprenticed to a wheelwright, but this was short-lived as the wheelwright went out of business. He then joined the survey party of T. W. Downes. For the next seven years he travelled widely through the Rangitīkei region, and during this time became acquainted with James Duncan, who had been the pioneer Presbyterian missionary in the region. Through this friendship Henry Fletcher decided to become a missionary to Māori.
His application to become a student for the Presbyterian ministry was approved and in 1889 he started his studentship. His base was Turakina, where he became a pupil of the Reverend John Ross with whom he studied theology, Greek and Hebrew. He also spent time learning Māori. In May 1893, in response to a request for a missionary in the Taupō area, Fletcher was sent to survey the possibility of setting up a mission station, and decided on the north end of the lake as the site. Arrangements for its establishment were completed in 1894.
On 17 January 1895 Henry Fletcher married Ada Morris at Hunterville. Three days later the couple set out for their new home at Taupō. Although the Catholic and Anglican missions had in the past been well established in Taupō, over the previous few years the members of these churches had been visited only spasmodically by their missionaries. However, as he commenced his work Fletcher faced indifference from many, and opposition from the adherents of other churches. Hard-working and dedicated, with a sense of humour and a gift for talk, Fletcher set about building his mission.
He rowed around Lake Taupō visiting every Māori pā on its shores. Nearer Taupō village he visited pā on foot. To overcome his transport problems his mission committee presented him with a penny farthing bicycle, an object of wonder to Māori. He was ordained a minister in 1898, and in 1900 made his way through rugged country to Taumarunui, where he persuaded the church to set up a mission in 1902. By 1901 he was holding regular services in Tokaanu, and three years later was operating five main mission stations in his district.
Fletcher was horrified at unhygienic conditions and the high infant mortality rate among Māori. He conceived the idea of establishing a boarding school for girls, where they would be educated in nursing care and hygiene. In 1902 he presented his plan to the General Assembly of the Presbyterian Church of New Zealand and obtained approval. Fund-raising followed, and on 13 April 1905 the premier, Richard Seddon, opened the school in the former manse at Turakina. Henry Fletcher was to see the school flourish and move to new premises in Marton in 1928.
Fletcher was a versatile man. With his carpentry skills and Māori assistance he built a church at Taupō and assisted in erecting buildings in the Urewera on exploratory visits there in 1916 and 1918. The advent of the steamer Tongariro in 1899 had enabled him to travel more easily to the south end of the lake. Holding an engineer's certificate for inland waters, he assisted in the ship's engine room.
The study of the heavens also fascinated him. His small telescope was soon discarded for one he built himself – six feet long with a four-inch lens. For many years he wrote astronomy notes for the Hawke's Bay Herald. Fletcher also contributed papers to the Journal of the Polynesian Society and the Transactions and Proceedings of the New Zealand Institute. He wrote mainly on the Māori history of Taupō, and also compiled an index of Māori names. He regularly contributed historical articles to the press and published a history of Māori missions, and two Māori-language readers.
In March 1925 Fletcher resigned from the Māori mission because of a dispute over salary scales. After 30 years Henry and Ada Fletcher left Taupō, where their family of five daughters and three sons had been born. Fletcher was inducted as minister in the parish of Normanby. In 1929 he moved to the parish of Seacliff–Warrington in Otago, and returned to Taranaki, to Ōpunake parish, in 1932. He resigned that year and died in New Plymouth on 22 January 1933. Ada Fletcher died in 1966.