Reginald Newton Biggs was born in England on 16 June 1831, the son of Mary Margaret Bree and her husband, Reverend George Biggs. He is first recorded in New Zealand as a freehold settler in the Wanganui area in 1855. By 1857 he was living at Koreromaiwaho, in the Turakina district, and subsequently he moved to Mingiroa, in the Rangitikei district. In both places he acted as a station manager for Major William Trafford. Mt Biggs, near the Mingiroa station, is probably named after him. He gained a reputation locally as an excellent horseman, a fine shot, and a powerful swimmer. A later photograph shows him to be a lean, confident man with large, worn hands. He moved to Tangoio in Hawke's Bay in 1862 or 1863. From October 1863 he became a regular informant for Donald McLean on local Maori affairs. He was by this time fairly fluent in Maori and became known (by transliteration) as Te Piiki. His letters reveal some standard prejudices. On one occasion he wrote of 'the niggers', but he also argued strongly for the necessity for equal pay and rations for the Maori and European volunteers in the campaigns on the East Coast.
He was appointed lieutenant in the Hawke's Bay volunteers on 22 April 1865 and commanded a flanking attack in the assault on the large Hauhau fortification, Pakairomiromi, at Waiapu, on 2 August 1865. No male prisoners were captured on that day: all were killed and the pa was burnt down. Biggs's deliberate shooting of Raharuhi Rukupo's protégé, Pita Tamaturi, when he was taken prisoner at Hungahunga-toroa pa on 11 October 1865, was the cause, in 1868, of Te Kooti's accepting a request for assistance in war, in the form of the gift of a famous greenstone mere, Tawatahi; the eventual killing of Biggs at Matawhero was the fulfilment of the compact.
Biggs was promoted to captain in the militia (deliberately backdated to 11 October) for his services in the Waiapu wars. He was dispatched to Gisborne and took part in the siege of Waerenga-a-hika between 17 and 22 November 1865, where Te Kooti, who had fought on the government side, was first arrested as a spy. On 17 November Biggs was also appointed a justice of the peace. He returned to his military camp at Wairoa in Hawke's Bay and then, after taking long leave in Christchurch, was appointed from Wairoa, in May 1866, to the command of the militia at Gisborne. He was almost certainly at Napier with Donald McLean in early June, on his way to Poverty Bay, when McLean turned down Te Kooti's request for a hearing of the accusations which had led to his imprisonment. Instead, on 5 June, McLean ordered the prisoners at Napier to be sent to the Chatham Islands.
Biggs himself became implicated in Te Kooti's revenge on those who had refused him justice. As magistrate at Gisborne from February 1867 he insisted that the prisoners be kept at the Chathams until the land confiscations at Poverty Bay were arranged, while his administration of land policies attracted much criticism and a widespread Maori refusal to co-operate. During Te Kooti's imprisonment Biggs, who had married Emily Maria Dudley in Christchurch on 27 June 1867, settled on land which had belonged to the former at Matawhero. His correspondence also establishes that he expected to benefit personally from the Poverty Bay confiscations. However, little had been agreed on when the Chatham Island prisoners escaped and landed just south of Gisborne on 10 July 1868.
Biggs set out to capture the prisoners. This pursuit of Te Kooti, who had asked that the ex-prisoners be allowed to go peacefully inland to settle, caused the wars that followed. From a military perspective Biggs had little choice, for the prisoners were well armed. They were also well led, and the government forces suffered a series of defeats. Regardless, Biggs was promoted to major on 1 August. Te Kooti later explained the Matawhero attack in November as the consequence of Biggs's determination to pursue him; if he had been left alone, he said, he would not have interfered with anyone. Early in November Biggs knew that an attack was imminent; he also knew that he could not guard effectively against it. The attack came early on the morning of 10 November 1868. Biggs was dragged out of his house and beaten to death; Emily, their infant son, George, and his nurse, were also killed.