A dependable officer who had risen swiftly through the ranks, Hicks conducted liaison and military duties for Cook, including command of shore parties in Rio de Janeiro and the kidnapping of a Tahitian chieftain in order to force indigenous assistance in the recovery of deserters.

Hicks' quick thinking while in temporary command of HMS Endeavour also saved the lives of Cook, Joseph Banks and Daniel Solander when they were attacked by Māori in New Zealand in November 1769.

[2] He enlisted or was pressed into military service at Ripon and first appears in navy muster-books as serving as able seaman and master's mate aboard HMS Launceston from 1766.

He is not mentioned in the journals of either Cook or the Royal Society supernumeraries Joseph Banks and Sydney Parkinson until Endeavour reached the Portuguese port of Rio de Janeiro on 13 November 1768.

Instead, Hicks and master's mate Charles Clerke were detained on shore while answers were sought from Cook regarding his vessel, armaments and number of crew.

On arrival at Rio's docks he objected when a Portuguese soldier boarded his boat and refused to leave, at which point he and his crew were arrested and taken under guard from the shore.

[7] Portuguese authorities accused Hicks of threatening their soldiers' lives and of displaying "petulancy and imprudence"; they asked that he be confined to Endeavour and not return to shore.

Hicks' threat succeeded – Monkhouse and the sailors were released, the Tahitians found and returned the deserters, and all were restored to Endeavour along with a peace offering of four pigs.

[13] In this role Hickes made the expedition's first sustained contact with indigenous Australians when more than a dozen gathered on the beach to watch his men collect water.

[3] As Cook recorded in his journal, the cause of Hickes' death was "a Consumption of which he was not free from when we saild from England so that it may be truly said that he hath been dieing ever sence, though he held out tolerable well until we got to Batavia.