In 1922, he was appointed as temporary demonstrator in petrology in the Sedgwick Museum, Cambridge, where he worked under Alfred Harker.
Phillips then began working towards a PhD thesis, with a study of the petrology of the igneous rocks of the Shetland islands.
[1]: 5 After completing his PhD, Phillips remained in Cambridge, where he began to focus on the microscopic structure of metamorphic rocks.
After a laboratory fire caused extensive damage to his research records, he retired on medical grounds and returned to Cambridge in late 1947 to convalesce.
[1]: 41 Phillips was elected Professor of Mineralogy and Petrology at Bristol in 1964, and was both deputy dean of the science faculty, and acting head of department, from 1966 to 1967.
He also published a revised edition of Herbert Smith’s Gemstones,[4][5] and in his retirement completed a translation from German of Bruno Sander's two-volume 1948 memoir on rock fabrics and structural geology, Einführung in die Gefügekunde geologischer Körper.
[6] Phillips was awarded the Murchison Fund of the Geological Society of London in 1938 ‘for his contributions to metamorphism and structural petrology’.