Rex C. Larkin was an active participant in harness racing associations. A native of Pittsburgh, Pennsylvania, he was a director of The Hambletonian Society, president of the Lexington Trots Breeders Association, and other Standardbred associations. Through his wife Ethel, Larkin purchased the Poplar Hill Farm in 1940 and established one of Kentucky's top breeding farms. They owned and raced such Standardbred greats as Ann Vonian, her son Poplar Byrd and Poplar Byrd's son, Bye Bye Byrd. Rex and Ethel Larkin died in a plane crash near Cincinnati in 1965.
Published in the Harness Racing Museum's 1994 book, The Immortals