Born in Thames on 14 July 1935, Phillips was educated at Westport Technical College and Christchurch Boys' High School. He studied at Canterbury University College, from where he graduated with an MSc with first-class honours in 1958. After a PhD at the University of Cambridge and post-doctoral research at McGill University, he returned to lecture at Canterbury, rising to the rank of professor in 1966.
In 1968, Phillips was elected a Fellow of the Royal Society of New Zealand, and in 1979 he won the society's Hector Medal.
In 1959, Phillips married Pamela Anne Johnstone, and the couple went on to have two children. He died in Christchurch on 24 September 2023, at the age of 88.