Norman Alexander Leslie was born in 1870, the son of John Leslie. He was educated at Sherborne School. He married Mimy Muriel Gambier in 1898 (died 1934), with whom he had three daughters.

He was a partner in the firm of Law, Leslie and Co, a director of George Thompson and Co Ltd, and a well-known member of the Baltic Exchange. During the First World War, he volunteered for service in the Transport Department of the Admiralty, 1915-16. He transferred to the newly formed Ministry of Shipping, where he was involved in inaugurating the convoy system, 1917-18.

He died on 23 October 1945.

He was created CBE, 1918, and KBE, 1919.

His publications include: "The System of Convoys for Merchant Shipping 1917 and 1918" (1919).