Jean Emily Hay was born on 17 June 1903 at Collie, Western Australia, the daughter of Emma Jane Langridge and her husband, William Arthur Hay, a clergyman. In 1911 her father moved with the family to New Zealand to take up an appointment with the Mount Eden Methodist Church. Three years in Auckland were followed by five years in Dunedin, where she went to Arthur Street School and Otago Girls' High School, and four years in Timaru, where she attended Timaru Girls' High School.
She began her teaching career as a probationary teacher at Timaru Main School in 1922; at the same time she taught Sunday school at the Banks Street Methodist Church. When her father took up an appointment at Durham Street Methodist Church, Christchurch, in 1923, Jean Hay moved with him and taught at Phillipstown Infants' School before entering Christchurch Training College in 1924. On graduating two years later she taught at Somerfield School, New Brighton School and at the Normal School.
From 1929 until 1932 Hay was in London studying the Dalcroze method of teaching music and movement to young children. She returned in 1933 with a certificate in Dalcroze Eurhythmics, intending to become a specialist teacher, but retrenchment during the depression meant she had to return to classroom teaching. She became a staff member of the Normal School in Cranmer Square, remaining there for 17 years, for part of that time as infant mistress. A part-time instructor in infant method at the Teachers' Training College from 1944, in 1949 she became a full-time lecturer. As women's warden during her last four years there she was responsible for about 300 women students at any time.
Jean Hay was a trail-blazer in early childhood education. Throughout her years on the training college staff she was active on a number of committees set up by the Department of Education to study reading, number and arithmetic and to revise the school syllabus. She lectured in music at the Kindergarten College and was involved in the playcentre movement. She was frequently asked to lecture at refresher courses, at WEA courses, and at Parent–Teachers' Association meetings.
However, she is most widely remembered for her music and movement broadcasts to schools, which she did for 25 years, introducing her programme with the familiar announcement, 'Rhythm for Juniors by Jean Hay'. She never missed a broadcast and they were enjoyed in schools and homes throughout New Zealand, earning her thousands of fans. During outbreaks of poliomyelitis she provided advice to families and received 3,000 letters of appreciation. Hay and her colleague, Dorothy Baster, were the pioneers of school broadcasting in New Zealand.
After retiring in 1960 Jean Hay took a trip to Britain and Europe, and was then invited to take up a temporary position as assistant principal at the Kindergarten College, which she did for two years.
She was a member of the Durham Street Methodist Church, Christchurch, for more than 50 years and superintendent of the Sunday school for 40 years, always making her classes stimulating and colourful by the use of music, movement and puppets. She was encouraging and helpful to the other Sunday school teachers and took their training seriously. A valued member of her church congregation, Jean Hay was remembered with great fondness. She was outgoing, cheerful and capable. The abiding interest of her life was the physical, emotional, educational and spiritual development of children. The three important needs of the young child, she wrote in 1945, were security, the need for active experience and the opportunity for self-assertion and independence. Jean Hay did not marry. She died in Christchurch on 14 February 1984.