After his return to New Zealand Joyce was hospitalised, mainly from the effects of snow blindness, and according to his own account had to wear dark glasses for a further 18 months. During this period he married Beatrice Curtlett from Christchurch. He was now probably unfit for further polar work, although he attempted, unsuccessfully, to rejoin the Navy in 1918. In September 1919 he was seriously injured in a car accident, which led to months of convalescence followed by a return to England. In 1920 he signed up for a new Antarctic expedition to be led by John Cope of the Ross Sea party, but this venture proved abortive. He continued to maintain his claims to financial compensation from Shackleton, which caused a breach between them, and he was not invited to join Shackleton's Quest expedition which departed in 1921. He applied to join the British Mount Everest expedition of 1921–22, but was rejected.
He was in the public eye again in 1923 when he was awarded the Albert Medal for his efforts to save the lives of Mackintosh and Spencer-Smith during the 1916 depot-laying journey. Richards received the same award; Hayward, and Ernest Wild, who had died of typhoid during naval service in the Mediterranean in 1918, received the award posthumously. In 1929 Joyce published a contentious version of his diaries under the title The South Polar Trail, in which he boosted his own role, played down the contributions of others, and incorporated fictitious colourful details. Thereafter he indulged in various schemes for further expeditions, and wrote numerous articles and stories based on his exploits before settling into a quiet life as a hotel porter in London. Bickel's assertion that Joyce lived into his eighties, beyond the date (1958) of the first Antarctic crossing by Vivian Fuchs and his party, is not supported by any other source. Joyce died from natural causes, aged about 65, on 2 May 1940. He is commemorated in Antarctica by Mount Joyce at 75°36′S 160°38′E / 75°36′S 160°38′E / Mount Joyce).
The polar historian Roland Huntford sums up Joyce as a "strange mixture of fraud, flamboyance and ability". This mixed assessment is endorsed in the assortment of views expressed by those associated with him. Dick Richards of the Ross Sea party described him as "a kindly soul and a good pal", and others shared the favourable opinions expressed by Scott and Markham, confirming Joyce as a "jolly good sort", though unsuited for command. On the other hand, Eric Marshall of the Nimrod Expedition had found him "of limited intelligence, resentful and incompatible", while John King Davis, when refusing to join the Imperial Trans-Antarctic Expedition, told Shackleton: "I absolutely decline to be associated with any enterprise with which people of the Joyce type are connected".
Joyce's versions of events recorded in his published diaries have been described as unreliable and sometimes as outright invention—a "self-aggrandizing epic". Specific examples of this "fabulism" include his self-designation as "Captain" after the Ross Sea expedition; his invented claim to have seen Scott's death tent on the Barrier; the misrepresentation of his instructions from Shackleton regarding his sledging role, and his assertion of independence in the field; his claim to have been offered a place on the transcontinental party when Shackleton had made it clear he did not want him there; and his habit, late in life, of writing anonymously to the press praising "the famous Polar Explorer Ernest Mills Joyce". This self-promotion neither surprised nor upset his former comrades. "It is what I would have expected", said Richards. "He was bombastic [...] but true-hearted and a staunch friend". Alexander Stevens, the party's chief scientist, concurred. They knew that Joyce, for all his swaggering style, had the will and determination to "drag men back from certain death". Lord Shackleton, the explorer's son, named Joyce (with Mackintosh and Richards) as "one of those who emerge from the (Ross Sea party) story as heroes".