His fiction was only a sideline to his journalism career, which might explain his relatively low output. One of the best-paid journalists of his era, Merritt made $25,000 per year by 1919, and at the end of his life was earning $100,000 yearly—exceptional sums for the period. His financial success allowed him to pursue world travel—he invested in real estate in Jamaica and Ecuador—and exotic hobbies, like cultivating orchids and plants linked to witchcraft and magic (monkshood, wolfbane, blue datura—and peyote and marihuana).
Merritt married twice, once in the 1910s to Eleanore Ratcliffe, with whom he raised an adopted daughter, and again in the 1930s to Eleanor H. Johnson. He maintained an estate in Hollis Park Gardens on Long Island, where he accumulated collections of weapons, carvings, and primitive masks from his travels, as well as a library of occult literature that reportedly exceeded 5000 volumes. He died suddenly of a heart attack, at his winter home in Indian Rock Keys, Florida, in 1943.
His reputation has not stood well over the years among speculative fiction fans and critics (with the singular exception of The Ship of Ishtar, a universally hailed classic of the fantasy genre), but at one time he was a major influence on H.P. Lovecraft and highly esteemed by his friend and frequent collaborator Hannes Bok, by then a noted SF illustrator.
Merritt's stories typically revolve around conventional pulp magazine themes: lost civilizations, hideous monsters, etc. His heroes are gallant Irishmen or Scandinavians, his villains treacherous Germans or Russians (depending on the politics of the time) and his heroines often virginal, mysterious and scantily clad.
What sets Merritt apart from the typical pulp author, however, is his lush, florid prose style and his exhaustive, at times exhausting, penchant for adjective-laden detail. Merritt's fondness for micro-description nicely complements the pointillistic style of Bok's illustrations, and often serves to highlight and radicalize the inherent fetishistic tendencies of pulp sf.
In 1917, he published his first fantasy, "Through the Dragon Glass", in Argosy All Stories Weekly. This was followed by many more tales, including People of the Pit (1918), The Moon Pool (1919), The Metal Monster (1920), The Face in the Abyss (1923), The Ship of Ishtar (1924), The Woman of the Wood (1926), Seven Footprints to Satan (1927), Burn, Witch, Burn! (1932), Dwellers in the Mirage (1932), Creep, Shadow! (1934), and The Drone Man (1934).
The Fox Woman and the Blue Pagoda (1946) combined an unfinished story with a second, concluding part that was written by Merritt's friend Bok. The Fox Woman and Other Stories (1949) collected the same fragment, minus Bok's conclusion, with Merritt's short stories. The book The Black Wheel was published in 1948, after Merritt's death; it was written by Bok using previously unpublished material as well.Several of Merritt's works have sometimes been cited as possible influences for the hit ABC television series Lost. Several fan websites have noted striking similarities between Merritt's work, The Moon Pool, and the plot of the ABC drama. Thus far, the creators have not commented concerning the similarities or possible references.