Wimberley was educated at Alton Burn, Nairn, Wellington College, followed by Cambridge University. In December 1914, four months after the outbreak of the First World War, he entered the Royal Military College, Sandhurst and, on 11 May 1915, he was commissioned as a second lieutenant, into his grandfather's regiment, the Queen's Own Cameron Highlanders. His first posting was with the 3rd (Militia) Battalion of his regiment at Invergordon before his eventual posting, in September, to the 1st Battalion on the Western Front. The battalion, a Regular Army unit, formed part of the 1st Brigade of the 1st Division. In October Wimberley, now aged 19 and the machine gun officer of his battalion, fought in the Battle of Loos.