John Ashworth Nelder was born in 1924 in Dulverton, Somerset, England. He received his secondary education in nearby Tiverton at Blundell's, a "public" [that is to say, privately funded] school that he attended as a day pupil. In 1942, he entered Sidney Sussex College, Cambridge University, to read mathematics. His studies were interrupted after one year by war service and he trained as an RAF navigator in South Africa. He returned to Cambridge in 1946 and complete his studies, graduating a "wrangler" [the Cambridge University term for one who graduates with a first in mathematics] in 1948. He stayed on at Cambridge for a further year and completed the diploma in statistics in 1949.

In 1950, he was appointed head of the statistics section at the National Vegetable Research Station at Wellesbourne. In 1955, he married Mary Hawkes. They have a son and a daughter. He spent one year (1965-1966) on leave of absence from Wellesbourne in Adelaide as a research fellow at the Waite Institute. During this time, he started to develop the computer program, Genstat, which incorporated ideas of "general balance" that he had developed for the design and analysis of experiments. In 1968, John succeeded Frank Yates as head of statistics at Rothamsted Experimental Station, Harpenden. At Rothamsted, developing ideas he had earlier published in Biometrics, he started a collaboration with Wedderburn that resulted in a paper on generalized linear models that was to revolutionize statistical analysis. This modeling approach formed the sole raison d'être of the statistical package GLIM and is now incorporated in other major statistical packages such as Genstat, Splus and SAS. During his time at Rothamsted, he was appointed as a visiting professor at Imperial College London (1972), which led to his collaboration with Peter McCullagh in writing a book, Generalized Linear Models. Since his retirement in 1984, he has continued as a visiting professor in the Department of Mathematics at Imperial. He is a familiar figure at Harpenden Station, waiting to catch the train to London.

John Nelder has received many honors for his statistical work. He was awarded the Guy Medal in Silver of the Royal Statistical Society in 1977 and elected a Fellow of the Royal Society in 1981. He has served both the International Biometrics Society (1978-1979) and the Royal Statistical Society (1985-1986) as president. In 1981, the Université Paul Sabatier, Toulouse, granted him and honorary D.Sc. He has published two books and over a hundred papers, but these numbers do not do justice to his influence on statistical modeling, which is enormous. A hallmark of his work is the way that statistical and mathematical insight is combined with deep numerical, algorithmic and computational understanding to forge original analytic tools of great generality and high applicability. He is unusual among theoreticians in the practical interest he has shown in planning experiments and analyzing data. Since his retirement, he has continued to be active in research and has started a collaboration on hierarchical generalized linear models with Youngjo Lee. In this work, he hopes to do for random-effect models of the exponential class what he has already achieved for fixed-effect models.