His books include historical fiction and biography, often set on sailing ships, and stories of boys from Polynesia, Asia and indigenous American cultures.

[2] In the summer of 1922, Sperry was introduced to Kenneth Emory, an ethnologist at the Bishop Museum, Honolulu, by his foster sister, Anne Kinnear.

[4] before sailing to San Francisco in June 1925[5] Returning to New York in 1925, he worked in an advertising agency, "drawing vacuum cleaners, milk bottles, Campbell's Soup, etc.,",[6] then he had steady work as an illustrator of pulp romances, primarily for All-Story Love Stories for the Frank A. Munsey Company,[7] and adventure and romance newspaper serials for Metropolitan Newspaper Service/United Feature Syndicate, including many 72-part stories by Mildred Barbour.

Coloured as they were by the prevailing attitudes of his day, Sperry's ethnological works for young readers would by critics of today be stigmatized as condescending in their approach: it is all too easy to lose the historical perspective that would credit him with enlightenment and objectivity, given their date of publication.

On February 13, 1940 Call It Courage was published by The MacMillan Company, the story about a young boy on the island of Hikueru in Polynesia written and illustrated by Sperry.

"[13] Sperry purchased a farm in Thetford Center, Vermont, in the late 1930s, and then moved to Hanover, New Hampshire, at the beginning of World War II.