Green left Oxford in 1926 without taking a degree and returned to Birmingham to engage in his family business. He started by working with the ordinary workers on the factory floor of his family's factory, which produced beer-bottling machines, and later became the managing director. During this time he gained the experience to write "Living", his second novel, which he worked on during 1927 and 1928. In 1929, he married his second cousin, the Hon. Adelaide Biddulph, also known as 'Dig'. They were both great-grandchildren of the first Baron Leconfield. Their son Sebastian was born in 1934. In 1940, Green published "Pack My Bag", which he regarded as a nearly-accurate autobiography. During World War II Green served as a fireman in the Auxiliary Fire Service and these wartime experiences are echoed in his novel "Caught"; they were also a strong influence on his subsequent novel, "Back".