He was born in Nancy, France to Sir Henry John Cumming, a general in the British Army and received naval education at the Royal Naval College in Portsmouth. Cumming served as a midshipman in the Mediterranean and North America before being promoted to lieutenant in 1840 for his actions in the Syrian War. He remained with the Mediterranean Fleet until appointed to HMS Frolic, a sloop stationed in South America. Whilst detached from Frolic and in command of a small pinnace on 6th September 1843 Cumming and seven men boarded a Portuguese slave ship, subdued her 27-man crew and brought her back to Rio de Janeiro. He had expected to be promoted for his efforts but was overlooked he resented the decision for the rest of his life. Cumming spent some time in the Navy’s Experimental Squadron before being promoted commander on 9th November 1846.
Cumming’s first command was HMS Rattler, stationed off West Africa, during which he captured another slave ship. He saw active service against the Russians during the Crimean War, captaining the frigate HMS Gorgon and being promoted to post-captain on 19th April 1854. Subsequently, Cumming was transferred to HMS Conflict and, in company with HMS Amphion, was able to capture the Baltic Sea port of Libau without firing a shot. Towards the end of the war he took command of the ironclad floating battery HMS Glatton but arrived in the Black Sea after the peace had been agreed. He returned to the UK in time for Glatton to take part in Queen Victoria‘s 1856 Fleet Review. Cumming was appointed captain of the frigate HMS Emerald on 14th May 1859 and remained with the ship until the end of her Royal Navy career on 7th November 1863. Emerald served in the Channel Fleet, the Baltic Sea and Admiralty propeller trials. She also made several trips to the Americas including “one of the quickest passages on record” to Bermuda in 1860. After her decommissioning Cumming was appointed a Companion of the Order of the Bath, served aboard HMS Victory and Duke of Wellington and in the Packet Service.
Cumming achieved flag rank on 27th February 1870 when he was promoted to rear-admiral. He served for a while as a port admiral before becoming the Naval Commander-in-Chief of the East Indies in 1872, remaining there until 1875. Cumming continued to receive promotions, becoming vice-admiral in 1876 and admiral in 1880, he retired from the Navy in 1880. In retirement he lived at Foston Hall, near Derby. Cumming was appointed Knight Commander of the Order of the Bath as part of Queen Victoria‘s Golden Jubilee celebrations on 21st June 1887 he died in London on 17th February 1893.