Harry Delamere Dansey and Roger Ingram Dansey were sons of Englishman Roger Delamere Dansey, a postmaster, and his wife, Wikitoria Ngamihi Kahuao. Harry was born at Tapuaeharuru (Taupo) on 7 November 1874 and Roger at Ohinemutu on 19 April 1885. Their mother was the daughter of Ihakara Kahuao, leader of Ngati Rauhoto hapu of Ngati Tuwharetoa. She also had connections to Te Arawa and Ngati Raukawa.
Harry did his primary schooling in Rotorua, then went on to board at Auckland College and Grammar School. He joined the civil engineering section of the railway service as a cadet, his first posting being to Ngaruawahia. He had a flair for languages and was regarded with awe by the other Maori there, who, taking him for a Pakeha, were continually astonished by the perfect Maori he spoke. He also spoke fluent French. Following his time in Ngaruawahia, Harry transferred to the railway workshops in Christchurch and began studying at the School of Engineering, Canterbury College. He may well have been the first qualified Maori engineer.
He then transferred to Dunedin as a draughtsman and was appointed engineer in charge of construction in the Otago railway district. The Dunedin railway station was constructed under his supervision. He married Winifred Mona Orr at Ashburton on 16 October 1906; she died at Dunedin on 19 February 1908. There were no children of the marriage. Around 1910 Harry Dansey went to Britain to continue his engineering studies and to work on underground railway projects, including the London Underground. He spent time at the University of Edinburgh and, later, in Germany. He had particular expertise in light railways and fuels, and on his return to New Zealand he was made responsible for the design and construction of the Auckland–Pukekohe line duplication.
Like his brother, Roger Dansey left Rotorua for his secondary schooling, completing his education at Christ's College, Christchurch, in 1902, after which he became apprenticed for six years to a Dunedin engineering firm, John McGregor and Company. He then studied engineering at the University of Otago. His sporting ability earned him a place in the New Zealand Universities rugby team to tour Australia, and he became both an Otago and a South Island representative. He played for the Maori All Blacks in 1910 and 1911. Harry had been an athletics champion at high school and captain of the Canterbury College rugby team in 1899.
On 18 January 1912 Roger Dansey married Sarah Daisy Millar at Dunedin and commenced a new career as manager of the Oban Hotel. Their only child, Roger Delamere Tahere, was born in December of that year. The family then moved to Wellington where Roger took control of a Lower Hutt hotel, remaining there until the outbreak of war in Europe in 1914.
Roger sailed for Egypt in February 1915, as an officer in the Maori Contingent of the New Zealand Expeditionary Force. After a week at El Zeitûn camp near Cairo he was detailed for garrison duty at Ghajn Tuffieha camp, Malta. A popular officer and natural leader, he was promoted to captain in October 1915. He was instrumental in the rushing of the trenches in the battle of Sari Bair at Gallipoli, and together with Captain Pirimi Tahiwi introduced the haka 'Ka mate, ka mate, ka ora, ka ora' on the Gallipoli hills.
Invalided to England after being gassed during the fighting on the Somme, in January 1917 Roger Dansey was given the responsibility of organising light railway operations in France. In December he was promoted to major. He was to remain overseas for nearly nine years after the war ended, assisting in the rehabilitation of Belgium.
Harry Dansey was nearly 40 years old when war broke out. Despite having a reserved occupation, he enlisted. He sailed in the second draft of the Maori Contingent, and held the rank of second lieutenant. On arrival in Egypt he was posted to the Otago Infantry Regiment as a machine-gun specialist. In the reorganisation that followed the Gallipoli campaign, he was transferred to the New Zealand Pioneer Battalion. Promoted to lieutenant, he served as a Lewis machine-gun officer in France.
By January 1917 Harry had been mentioned in dispatches and was appointed second-in-command of a company in the field. His engineering qualifications were to prove invaluable. The following month, seconded for duty as II ANZAC Corps (later XXII Corps) tramway superintendent, he was placed in charge of railway construction and transport organisation for the battle area. The evacuation of wounded troops was also his responsibility. He was promoted to captain in April, and in January 1918 he was awarded the Military Cross for 'distinguished services in the field'. From 2 October until 26 December 1918 he performed the duties of bridging officer, XXII Corps.
Harry Dansey returned home at the end of the war. On 30 October 1919 at Auckland he married Winifred Patience Barter; they were to have three sons and a daughter. He ran an engineering consultancy in Auckland until 1930 when he retired to Rotorua. As president of the Rotorua Chamber of Commerce, Harry was as active in retirement as he had been through his earlier life. He petitioned Parliament in 1936 over the boundaries of the Tatua East block. In 1938 he unsuccessfully opposed Sir Apirana Ngata for the Eastern Maori parliamentary seat. He was elected mayor of Rotorua in 1941, an office he held for just a year before his death on 29 June 1942. He was survived by Winifred and their four children.
Returning to New Zealand around 1927, Roger Dansey, with his wife and son, settled in Rotorua, where he was appointed welfare and unemployment officer of the Native Department. Poor health obliged him to take early retirement in 1935. He assumed a very active civic role. The personality he brought to the Rotorua Borough Council's Publicity and Amusement Committee and the organisation of the town's Christmas and New Year celebrations ensured his public prominence.
Roger Dansey died in Rotorua on 13 August 1938. The lasting effects of his war injuries had contributed to his early death. He is buried at the Muruika cemetery behind St Faith's Church at Ohinemutu, alongside his brothers Harry and George, and their Te Arawa kinsmen with whom they had served in Gallipoli and in France.