Born in 1886, in Ditheringon, Shropshire, Leonard started his career with second division Glossop. Playing in the reserves at inside left, he was the top goal scorer, and had built up a reputation as a “bustling forward, and good shot.”
Manchester City saw his potential signing him in October 1910. Although the fee was undisclosed it was reported that the Hyde Road club had had to pay “pretty smartly” for him. He made forty-one first team appearances, and scored two goals in his four seasons with the club.
A move to Dundee occurred in early December 1913, shortly after he had been permanently suspend by City for “alleged misconduct.” He had been playing as a left half-back, but Dundee wanted him to play as a left-half. Much was expected of him on his debut against Dumbarton on the 6th December, and he rose to the occasion scoring in a 5-1 home win. Len soon settled in at Dens Park, catching up with former City teammates Jack Lyall and Tom Kelso.
At the start of January Len was red-carded in a match against Aberdeen, after a hefty tackle. The S.F.A. went on to impose a one-month ban, which both club and supporters thought severe.
Wall found the harsh, long Scottish winter hard, but he was a popular member of the team, having played “many brilliant games” in which his “deft touches were greatly appreciated”
As the season came to its conclusion, a few clubs showed interest in the player, but it was Crystal Palace who were successful in obtaining his signature, moving to London in June 1914.
When war broke out, Len enlisted in February 1915. He was a Private initially with the 4th King’s Shropshire Light Infantry before joining the Queen’s Royal West Surrey Regiment.
Leonard was sent home from Boulogne in April 1915, suffering from an illness, and was hospitalised in England, before recuperating at home. After returning to the front, he found himself in hospital in France in January 1916, before seeing action at Flanders.
He was a “runner” with the regiment, and in late 1917 was entrusted with delivering an important message from the front line back to Headquarters. Whilst trying to carry out this important task he was injured after the Germans started a heavy bombing barrage. However, he managed to complete the dangerous journey. For this, he was awarded the Military Medal. The Shrewsbury Chronicle reported that he had “proved himself as fearless on the battlefield as he was on the football field.”