Yeo was born about 1890 in Plymouth, Devon, England to Petty Officer Francis Yeo and his wife Rhoda Sarah Yeo (née Jarman). He had two elder sisters, Adelaide and Elsie. Three weeks after his birth, his father was killed aboard the Devonport torpedo cruiser, HMS Serpent, while en route to Sierra Leone, after hitting rocks off Cape Vilan, Spain.

At age 12, Yeo enlisted into the marine navy where he served as a bugler until 1911. He was promoted to leading seaman in 1912, petty officer in 1915, and warrant officer in June 1917.

Yeo was wounded on 31 May 1916, during the Battle of Jutland, while manning the guns aboard the battleship HMS Warspite and sustained terrible facial injuries, including the loss of upper and lower eyelids. He is known to have been admitted to Plymouth Hospital while waiting for a place at Queen Mary's Hospital in Sidcup, Kent, which was granted on 8 August 1917. He was treated by Sir Harold Gillies, an expert in treating the facially wounded and the first man to transfer skin from undamaged areas on the body. Yeo is one of the first patients to be treated with Gilles's technique; a form of skin transplantation called a 'tubed pedicle' flap.

After 3 years of medical treatment, in July of 1919, Walter Yeo was found to be fit for active service again. He underwent a further operation in August 1921, after which his disfigurement was recorded as 'improved, but still severe', and he was recommended for medical discharge, which took place on 15 December 1921. Walter later received further treatment for a corneal ulcer at the Royal Naval Hospital in Plymouth in 1938.

Walter married Ada Edwards in 1914, and had two daughters with her: Lilian Evelyn Yeo, born 21 October 1914, and Doreen Y. Yeo, born in 1919. He died in his hometown, Plymouth, where he had spent the majority of his life, in 1960 at the age of seventy.

Post WWI: In addition to his skill as a crossword compiler, teetotaler Walter became a pub Landlord and storesman at Monsen's Chandlery on Plymouth's Barbican.

Walter’s medical record held by Gillies Archives and now in the collection of the Royal College of Surgeons England.

Walter Ernest O'Neil Yeo