He was the younger brother of writer Ernest Hemingway and wrote six books, including a first novel entitled The Sound of the Trumpet (1953), based on Leicester's experiences in France and Germany during World War II.

The work was well-received and brought Leicester both recognition as a writer in his own right and significant financial rewards.

With the capital from the work, Hemingway created the micronation of New Atlantis on a raft off the coast of Jamaica,[3] intended to serve as a marine research headquarters.

With his second wife, Doris Mae Dunning, he had two daughters, Anne and author Hilary Hemingway.

[6] In 1982, Hemingway killed himself with a gunshot to the head[7][1] after having suffered several years from Type 2 diabetes, which required several operations.