Philpot was born in Clapham, London and trained at the Lambeth School of Art from 1900. He was only nineteen when he first exhibited at the Royal Academy. By the time he was elected to the Royal Academy in 1923 he was a well-established portrait painter. He painted society beauties, politicians, admirals, the King of Egypt and Oswald Mosley. A convert to Catholicism, he also produced paintings on religious themes and from early 1930s outraged his traditional audience with works which were overtly modernist in style.