Basil Bramston Hooper was born in Lahore, India, on 17 April 1876, the youngest of nine children born to William Hooper and his wife, Charlotte Elizabeth (Elisabeth) Candy. William Hooper, an Anglican priest and Church Missionary Society missionary, spent most of his life in India and from the age of two Basil and his brothers lived with their father's sister, Bessie Hooper, in Switzerland, or with relatives in England, rarely seeing their parents.
In 1885 the boys, accompanied by Bessie Hooper, emigrated to New Zealand, the younger children living with their aunt at Cambridge. Erratic schooling meant Basil finally completed standard six when aged 16. He was then apprenticed to the Cambridge builder William White. At 19 he decided to train as an architect, but first attended Queen's College, Auckland, to remedy the deficiencies in his education. In 1896 he was articled to the Dunedin architect J. L. Salmond for three years, leaving Salmond's office in December 1900. He left for England in February 1901 to further his studies.
Hooper initially worked for A. Beresford Pite, professor of architecture at the Royal College of Art and a leading member of the Art Workers' Guild, and subsequently for E. P. Warren, another member of the guild. He was also employed by the Housing Division of the London County Council's Architect's Department and briefly by Temple Moore and His Majesty's Office of Works. After being admitted as an associate of the Royal Institute of British Architects he returned to Dunedin in 1904.
Hooper was, in his own words, 'the first young architect to arrive in Dunedin from England, with ARIBA after my name, and up to date designs'; he quickly became one of Dunedin's leading architects. His first major commission, a woolstore for the National Mortgage and Agency Company of New Zealand, was followed by a house at the corner of George and Warrender streets (1905). The restrained simplicity of this unpretentious brick house contrasted with the prevalent late-Victorian taste for highly decorated villas, and established a new direction in Dunedin's domestic architecture. These same qualities appear in the modest timber houses he built for the Windle Settlement at Rosebery Street, Mornington, under the Workers' Dwellings Act 1905. The Stafford Street private hospital (1907), with its projecting and receding gables, demonstrates his skill at adapting his domestic idiom for institutional use.
On 29 April 1909, at Nelson, Hooper married Edith Jessie Seldon, a schoolteacher; they moved into his newly built house in Wallace Street, Roslyn. Following Arts and Crafts movement ideals he sought to realise in this building 'simplicity of detail, with picturesqueness of grouping', and aimed at 'a quiet, restful solidity'. The influence of the English architect C. F. A. Voysey, already apparent in this house, is increasingly evident in the imposing house for George Ritchie at 26 Heriot Row (1911–13), and becomes overt in the Scoular house, 319 York Place (1916). In his best houses Hooper reassembled Voysey's trademarks of rough-plastered walls, sloping buttresses, curved gutter brackets and sweeping roofs into designs that are distinctively his own and which respond to Dunedin's topography. Interiors are plain but meticulously crafted, enriched with finely detailed woodwork and often embellished with subtly coloured leadlight windows in art nouveau style.
Hooper's refined houses revitalised domestic architecture in Dunedin prior to the First World War, but he also carried out commercial and ecclesiastical commissions. He was supervising architect for St Paul's Cathedral from 1915 to 1919 and in 1922 prepared a design for St Mary's Anglican Church, Mornington; only the chancel was built to Hooper's design. The St Kilda Methodist Church Hall (1909, demolished 1985), a brick building in Byzantine style, revealed the influence of Beresford Pite. His commercial buildings, executed in unadorned brick with stone dressings, exhibit a restrained classicism also derived from the works of Pite and Warren.
In 1922 Hooper was an assessor for the Auckland University College building competition and the following year moved to Auckland. Domestic architecture continued to dominate his practice but his Auckland houses, mostly built in timber, never achieved the assured unity of his pre-war designs. A partnership with J. W. Rough ended early in 1926, due to a lack of paying contracts and other financial setbacks. The most substantial commission of his Auckland years was the YWCA Girls' Hostel, Myers Park, built in 1926 but demolished in 1985.
A lifelong Anglican, Hooper belonged to the congregation of All Saints' Church in Dunedin. He was a flautist in the Dunedin Choral Society's orchestra and was active in the Otago Lawn Tennis Club. In 1948 he retired having weathered the lean architectural years of the 1930s and the Second World War. He died at Waiuku on 3 February 1960, survived by a daughter and a son; Edith Hooper and another daughter had predeceased him. He was remembered as 'a very gentle, unassuming man' who had 'a shy and retiring disposition and was certainly the soul of integrity'; his buildings exhibit many of the same qualities.