Leonard was educated at Clifton Academy in Bristol. He joined the 1st West Lancashire Brigade of the Royal Field Artillery and was commissioned as an officer. The Regiment was posted to the Western Front with A Battery, 275 Brigade of the Royal Field Artillery in September 1915. During that period, Leonard was mentioned in despatches.
Leonard was killed near Ypres on 9th June 1917 and is buried at Lijssenthoek Military Cemetery in Belgium. At the time of his death, Leonard was engaged to be married to a young lady from Kent.
It seems that Leonard was killed while riding his Regimental horse “Blackie” because I found a mention on the Internet that he had left instructions in his Will that his medals should be buried with his horse. He must have left more than that because “Blackie” was apparently among the few horses repatriated after the end of the War. "Blackie" lived on until 1942 and when he died at the age of 35 in an RSPCA facility in Hunts Cross in Liverpool, he still bore the scars of the Shrapnel that killed his master.