William Arthur Greener Penlington was born on 8 October 1890 at Akaroa, Banks Peninsula, where his grandfather, a sawmiller, had settled in the late 1850s. The son of compositor William Penlington and his English-born wife, Annie Greener, he went to school in Akaroa and Hamilton. He then attended Auckland Training College, where he specialised in agricultural science, worked as librarian and science tutor, and took classes at Auckland University College. He graduated MA in 1912 and wrote a textbook, Science of dairying (1915), for use in secondary and technical schools.
During the First World War Penlington served as a company commander in the New Zealand Rifle Brigade in France and Belgium. Gassed at Messines (Mesen), he was invalided home and appointed secretary, and later consul, to the military administration in Western Samoa. On 30 October 1919, in Auckland, he married Elizabeth Nutter (née Miller). In December, now with the rank of major, he moved to Wellington to become director of vocational training for disabled servicemen.
In April 1922 Penlington was appointed acting director of the newly established Hastings Technical High School, which was initially accommodated in four brick classrooms erected for the district school in 1908. The local authorities in Hastings, Havelock North and Hawke's Bay County had bought 19½ acres of land for a new school. Public meetings and a petition signed by 2,000 people urged the government to begin construction, but the minister of education, C. J. Parr, told a large deputation this was financially impossible. He expressed surprise, however, to hear that 150 free-place pupils were travelling daily by train into Napier. As a result Hastings was placed third on the urgent list.
Penlington meanwhile began to put his stamp on the school. In his view, the first need was esprit de corps, 'the uplifting spirit in a body of people working together'. For an inspiring motto and badge he sought help from well-known local Māori. Paraire Tomoana proposed 'Akina', the word used to encourage canoe paddlers to 'strike hard'. For the school badge Dan Ellison suggested the huia, a bird esteemed for its nobility and loyalty. Penlington introduced a school uniform, a special Anzac Day service and a house system for sports; he also enlisted an All Black, Sam Gemmel, to coach the First XV rugby team. In 1925 a fine new school was erected, designed in Cape Dutch style by William's cousin, George Penlington, a government architect. Extensive grounds, with sports fields, agricultural plots, driveways and shelter trees, were laid out. The technical school was reconstituted as Hastings High School, with William Penlington as principal, and on 9 February 1926 242 pupils carried in their furniture and equipment.
'Pen', as he became known, had his own ideas on education. While they were appreciated by the first woman inspector of secondary schools, Jessie Hetherington, they were not generally liked in Hastings. He believed in co-education, which he had always had himself, and in indirect methods of discipline, not corporal punishment. Critical of 'highly abstruse, academic…education remote from the realities of life', he aimed to turn out the 'right kind of person' – honest, friendly, courteous, and reasonable – and stressed the importance of adaptability and open-mindedness. Education should meet physical, biological and emotional needs, he argued, before seeking to fulfil intellectual, artistic and religious goals. Teachers should not only equip their pupils to earn a living, but should endeavour to impart a sense of humanity and of striving, not for oneself, but for the team.
During his 23 years as principal Penlington's high ideals permeated the school, enabling him to achieve an acceptable balance between liberal and traditional education. Pupils were encouraged to stay on in the sixth form, to sit units for university degrees extramurally, and to exercise initiative and leadership in school affairs. Arts, music, sports and a widening range of extracurricular activities were promoted; school facilities were greatly extended and improved.
Although the boys' side of the school was supervised by S. I. Jones, the first assistant, and the girls' side by Marion Steele, the senior mistress, Penlington retained a firm control. Corporal punishment was very strictly regulated, despite accusations that he was too soft and too much of a gentleman. Penlington later reflected that it was the military aspect (form and house captains, prefects, school cadets, and Anzac Day commemorations) that had gained him the acceptance of local citizens. Business and professional families of Hastings, however, continued to send their children to private boarding schools, and New Zealand Railways continued to issue free passes for boys to go into Napier. This drained local support for the school and encouraged social segregation.
In adversity the community was well served by Hastings High School. After the 1931 earthquake, Penlington recruited 140 men and some of his senior boys for picket and patrol duties. From 1939 to 1945 the school's energies were directed to assisting the war effort, cadet and air force training, supporting ex-pupils on active service and remembering those who died. When he retired in May 1949, Penlington received warm tributes at a civic gathering of about 500 people. As an old pupil said, his 'understanding of the eccentricities of human nature had enabled him to send his pupils out into the world well fitted for the job ahead of them.'
In retirement Penlington was re-elected to the Havelock North Town Board (on which he had earlier served in 1925–26), and was a leading opponent of fluoridation. A self-taught watercolour painter 'who searched constantly for perfection', he had six months' tuition at a Sydney studio and exhibited regularly. He also reviewed books for the Hawke's Bay Herald-Tribune. Predeceased by his wife in 1971, William Penlington died in Hastings on 5 August 1982; there were no children of the marriage.