He had also published a few light-hearted novels - the first of these, A Boy's Marriage, came out in 1907 - but after World War I broke out, his literary output took on a more serious note. As war ended in 1918, his writings too resumed their former gaiety, in novels such as Young Mischief and Young 'Un. In 1924, The Cricket Match was published. This novel stands alongside A. G. Macdonell's England, Their England as one of the classic accounts of village cricket in English literature. The fictional village of Tillingfold was a recurring element in de Selincourt's work, and was based on his own village of Storrington at the foot of the South Downs.
In the immediate postwar years, Hugh and his wife Janet, lived at Sand Pit, a lush house in Sussex and had an open marriage. A close friend of Havelock Ellis, de Selincourt met Ellis's close friend, Margaret Sanger in 1920 and began an affair with her. When that ended he began an affair with Ellis's companion, Francoise Lafitte Cyon, which ended his friendship with Ellis.
The Saturday Match (1937) and Gauvinier Takes to Bowls (1948) were among de Selincourt's final books. He died in his home in Pulborough, Sussex at the age of 72. His widow Janet died in 1955.