Hemi Huata was the fourth child of Tamihana Huata, the first vicar of Wairoa Maori pastorate, who had succeeded the missionary James Hamlin in 1864. Tamihana was an important chief whose influence on events in the Wairoa area was significant, and Hemi inherited his father's mana. His mother was Ripeka, a woman of high rank from Rangiahua, and he had two elder brothers, Anaru Huata and Kunaita Pomare, both of whom died without living issue. He was born in 1866 or 1867 at Ramoto, Frasertown, north of Wairoa, of Ngati Kahungunu descent. His main hapu was Ngati Mihi on his father's side. His mother's hapu were Ngai Tama-te-rangi and Te Aitanga-a-Hinemanuhiri. Other hapu Hemi claimed were Ngati Hinetu, Ngati Kotore of Papuni, Ngati Paikea of Mohaka, Ngati Hikapi of Waikare (between Mohaka and Tutira), Ngati Hika of Te Reinga and Ngati Ruapani of Waikaremoana.
At a young age Hemi was taken to Heretaunga, the plains of central Hawke's Bay, to live with a relation while Te Kooti was active in the Wairoa district. When he was living there an aunt was caught pilfering peaches, and he became known as Hemi Pititi (Peach) Huata. In 1886 Hemi attended Te Aute College, at a time when John Thornton was headmaster and Apirana Ngata a fellow pupil. Hemi, who was also known as James Stuart, was a college prefect in 1890 and captained the 1891 college rugby team that won the Hawke's Bay championship and toured the South Island.
After leaving Te Aute Hemi went to Te Rau Theological College, Gisborne, and was ordained as a deacon in 1898. He became curate of Mohaka pastorate, and then vicar after being ordained priest in 1901. He travelled throughout his pastorate on his horse, preaching the gospel, christening new members, marrying couples and administering communion. He also visited the sick, offered many blessings and buried relations throughout the region.
Not long after he was ordained Hemi married Ropine Aranui of Ngati Pahauwera, of Mohaka. Their marriage was viewed as the beginning of the healing process between Ngati Pahauwera and the supporters of Te Kooti. Because of a pact between Tamihana Huata and Te Kooti, many of Tamihana's Ngati Kotore relations had taken part in the massacre when Te Kooti attacked Mohaka in 1869. Ropine's ancestor Matenga Te Aohia and other relations had been killed.
Due to Hemi's inheritance of his father's and mother's mana he became influential in the Wairoa district. He was curate of Wairoa from 1913 to 1919, and after his retirement from the Mohaka pastorate in 1934 he continued to officiate in his district. He was a very humble and peaceful man and was much loved by his people. He was an acknowledged keeper of Ngati Kahungunu whakapapa, and contributed to J. H. Mitchell's book Takitimu, and Apirana Ngata's Nga moteatea. Hemi also taught the tradition and whakapapa of Ngati Kahungunu to his son Te Okanga (Aussie), wrote down whakapapa, and kept diaries.
In the early 1920s there was much debate within the Anglican church about the movement founded by T. W. Ratana. Initially membership of the movement was considered to be complementary to church membership. Hemi Huata was Ratana leader at Wairoa, and supported Taranaki Te Uamairangi as an independent Ratana candidate against Apirana Ngata and others in the Eastern Maori electorate at the 1922 general election. When Ratana came to Mohaka in the early 1920s Hemi accompanied him to Wairoa and attended Christmas hui at Ratana pa. But in 1925 the Anglican church pronounced the Ratana movement schismatic and incompatible with Anglicanism. Hemi found that he could not support two faiths, and left the Ratana movement. However he did not discourage his relations from remaining followers of Ratana.
From 1923 to 1927 Hemi Huata and Ropine had a shop at Mohaka. The business was not very successful because they allowed many of their relatives to run up large accounts. Also some of Hemi's children would puncture cans of preserves, drink the juice and put them back on the shelves, the damage undetected until customers came to purchase the items.
Hemi and Ropine had 11 children. When their first grandchild was born, following traditional custom they took the child to raise as their own. Thereafter Hemi and Ropine raised many grandchildren and relations. Their son Wi Te Tau Huata often spoke of having 42 brothers and sisters. Hemi sent three daughters to Hukarere Native Girls' School, three sons to Te Aute College and two sons to other schools.
In the 1930s Hemi supported Apirana Ngata's Horohoro Native Land Development Scheme, through which some Ngati Kahungunu families were relocated to the Rotorua district to help Te Arawa to develop farms. He began to be acknowledged as one of the major speakers on marae throughout the Wairoa area. He had his own marae, Te Huinga-o-te-rangi-ora, at Ramoto. However, he supported the building of Takitimu meeting house at Waihirere (Takitimu) marae, near Wairoa, and was one of the original trustees. In 1937 Hemi Huata was a recipient of King George VI's Coronation Medal. During the Second World War he encouraged his sons to enlist. Wi Huata was chaplain to the 28th New Zealand (Maori) Battalion in Italy, and was awarded the Military Cross for his service.
On 13 October 1954 Hemi Huata died at Ramoto. He was buried on 17 October at Te Poho-o-Rakaihakeke cemetery, Ramoto, at his father's feet. Ropine was buried there when she died in 1959.