Cooper was about 27 years old and a private in the 2nd Battalion, 24th Regiment of Foot (later The South Wales Borderers), British Army during the Andaman Islands Expedition.

On 7 May 1867 at the island of Little Andaman, eastern India, in the Bay of Bengal, Private Cooper was one of a party of five (David Bell, Campbell Mellis Douglas, William Griffiths, Thomas Murphy) of 2/24th Regiment.

For the very gallant and daring manner in which, on the 7th of May, 1867, they risked their lives in manning a boat and proceeding through a dangerous surf to the rescue of some of their comrades, who formed part of an expedition which had been sent to the Island of Little Andaman, by order of the Chief Commissioner of British Burmah, with the view of ascertaining the fate of the Commander and seven of the crew of the ship " Assam Valley," who had landed there, and were supposed to have been murdered by the natives.

"Regiment, and the four Privates referred" to, gallantly manning the second gig, made their way through the surf almost to the shore, but finding their boat was half filled with water, they retired.

The four Privates behaved in an equally cool and collected manner, rowing through the roughest surf when the slightest hesitation or want of pluck on the part of any one of them would have been attended by the gravest results.