Landscape and portrait painter, born at Birkenhead, Cheshire. He studied at the Royal College of Art and the Slade, and also in Paris and Rome. He helped Sir William Richmond with decorations at the Old Bailey, London, 1906-8. He served in the Artists' Rifles, 1915-1918. He exhibited at the RA from 1919, being elected RA in 1951. He also showed at NEAC, RP, Leicester Galleries, Goupil Gallery and ROI. Examples of his work are in the collections of the Tate Gallery, Manchester City Art Gallery and Wakefield City Art Gallery.
Mason earned his living mostly by painting portraits, much in the style of Augustus John, with whom he shared a studio. He was engaged to fellow Slade artist Winifred Knights and produced a number of remarkable portraits of her.