Leach was commissioned into the Royal Engineers in 1866. He was 31 years old, and a captain in the Corps of Royal Engineers, British Army and with Bengal Sappers and Miners (British Indian Army) during the Second Anglo-Afghan War when the following deed took place on 17 March 1879 near Maidanah, Afghanistan for which he was awarded the VC. He died in Cadenabbia, Lake Como, Italy on 27 April 1913.