Thomas Samuel Grace was born to John Grace and his wife, Sarah Lawrence Cox, on 16 February 1815 in Liverpool, Lancashire, England. He married Agnes Fearon on 23 July 1845 at Whitehaven, Cumberland, and they had 12 children.
Thomas Grace's early education at a grammar school was brief, but by his mid 20s he was managing a firm in Liverpool. Success in business enabled him to make provision for his dependent parents, and, drawn to missionary work, he offered himself to the Church Missionary Society in 1844. He trained at his own expense, first privately and then at St Bee's College, from August 1846. He was ordained deacon to the curacy of Tideswell in Derbyshire in June 1848, and in June 1849 he received full orders.
Grace sailed for New Zealand on 11 February 1850 on the Fairy Queen, with his wife and two children, and arrived in Auckland on 9 July 1850. It was intended that he should establish a new station at Taupo, but as the Reverend William Williams was abroad, he was diverted to Turanga, Poverty Bay, where he stayed from October 1850 to the end of 1853. His approach to the temporal well-being of the Maori differed markedly from that of William Williams, who sought rapid racial amalgamation. Grace encouraged the Maori to ask for a fair price for their produce, to become familiar with money and figures rather than to barter for goods, to build and sail their own coastal vessels, to raise stock profitably, and to use ploughs. He opposed the sale of Maori land and consequently became unpopular with local settlers.
In 1854 Grace, then resident in Auckland, was responsible for an anonymous circular in Maori, Ko etahi patai ki te hunga Maori mo te hoko wenua (Some questions to the Maori people about the selling of land). Phrased along catechetical lines with Scripture references for answers, it counselled Maori not to part with land. Although few of the 250 copies were distributed, official inquiries and complaints to Andrew Sinclair, the colonial secretary, followed. Grace's colleagues distanced themselves, but the CMS committee in London was sympathetic to his views, if not his methods.
The CMS requested Grace to proceed with the establishment of a mission station at Taupo. On preliminary expeditions in 1853 and 1854 Grace selected Pukawa as the most suitable site. Seventy acres were set aside under the mana of the great Ngati Tuwharetoa leader Iwikau Te Heuheu Tukino III. When this offended a rival Maori leader, Te Herekiekie, Grace was able to use the occasion to bring about a reconciliation. The Grace family arrived at the station on 19 April 1855, after a slow and arduous journey from the east coast. The final stage from Tarawera took almost eight weeks and required large parties of Maori to carry baggage.
Grace's expectations were high. Initially he was critical of the state of Christianity at Taupo and the quality of teaching, but gradually his reports became more favourable. His work was interrupted when on 24 May 1856 the first raupo mission house was burnt, together with many possessions. This was a temporary setback. The raupo dwelling was replaced by a substantial, two-storeyed mission house, and an industrial school, boarding school, cottages and other buildings were also established.
Distance from larger settlements and food shortages were among the difficulties encountered by the Grace family. They continued to rely on European goods and food, and keeping the mission station supplied was a strain. However, as Grace opposed the official policy of rapid racial amalgamation and supported Maori economic independence, isolation was often an advantage. He encouraged sheep farming, and, later, imported machinery, so that the people could learn to spin and weave. This latter project was thwarted when war broke out.
As the result of a great meeting of North Island tribes at Pukawa in November 1856, Grace was again the subject of official complaints. Both Maori and Europeans alleged that he had encouraged, or even instigated, the King movement. Through the Colonial Office Donald McLean urged the CMS to remove him. They declined to act without reference back to New Zealand. Grace was able to rebut the charges and to point to the opposition he had given to the movement, although he blamed government policy for the war in Taranaki. While Iwikau Te Heuheu Tukino III, the protector of the mission, was still alive, the Taupo Maori stayed neutral, but later when Horonuku Te Heuheu Tukino IV became leader, sections of the people sided with the Waikato tribes. The district became increasingly unsettled, and on 8 October 1863 the Grace family left Pukawa.
Grace became one of the very few itinerant missionaries active among the Maori. Travelling from Auckland until 1872, and then from Tauranga, he journeyed repeatedly into the interior. On several occasions his life was threatened. Grace was with the Reverend C. S. Völkner at Opotiki in March 1865. After Völkner had been killed by Pai Marire followers, it was Grace's turn to be interrogated. However, he was not closely guarded and after 16 days in captivity escaped to the naval ship Eclipse, which was standing offshore. He narrowly missed an encounter with Te Kooti in 1867, and was also saved from an ambush at Pukawa, planned in revenge for Maori deaths at Rangiaowhia. He subsequently arranged to have a pamphlet printed in Maori, compiled by Archdeacon R. Maunsell. Entitled Nga minita i roto i te whawhai (The ministers involved in the war), it refuted charges against churchmen during the wars.
Grace's contacts with adherents of Pai Marire convinced him that their interest in Christianity was strong, and that their movement was an expression of a more widespread Maori desire for greater religious autonomy. The establishment of the Maori church, the goal of the CMS, was a pressing concern for Grace. He made a strong case for a Maori bishop, but it was some 50 years before this position was created. His attempts to further Maori participation in the administration of church lands were rejected by the CMS. His plan for a school which would train a Maori élite to lead in church and secular matters was not realised.
During a visit to England from June 1875 to late 1876 Grace gained the CMS's support for the proposed reoccupation of Taupo. He hoped that his son, the Reverend T. S. Grace junior, would live there and extend his work into the King Country. However, Thomas Grace senior's health failed and the long-cherished plan was not undertaken. He died on 30 April 1879 at Tauranga at 64 years of age.