Malleson was born in Croydon, Surrey, England. Despite his unassuming appearance, he was married three times, and had many relationships. In 1915, he married the aspiring actress Lady Constance Annesley. Like her, he was interested in social reform, one of his plays being on the subject of the Tolpuddle Martyrs. They were divorced in 1929 and Malleson later married Joan, who died in 1956. His third wife was Tatiana Lieven.
His best-known films include: