He was the younger brother of writer Ernest Hemingway, hw wrote six books, including the novel The Sound of the Trumpet (1953), which dealt with Leicester's experiences in France and Germany during World War II.
In 1961 he wrote a biography about his brother Ernest Hemingway with the money he earned from the book he founded the micronation New Atlantis outside of Jamaica. In 1966 the micronation was devastated by a storm.