Sea Star is the central character of Sea Star, Orphan of Chincoteague published in 1949. Marguerite Henry was visiting Chincoteague for Pony Penning 1948 when an orphan foal was found on Assateague. She writes as such in the book's forward. The foal was born to a Wallops Island mare that had been moved to Assateague. The Wallops Island ponies had difficulty adapting to Assateague and the mare was one of the casualties. The foal was found on Assateague on July 29, 1948 and two men caught him. The colt was then sold to a resident of Chincoteague but he ultimately only lived a couple of days. The colt's story was documented in the journal of island historian Victoria Pruitt.

Journal entry about the colt, Museum of Chincoteague Island display

The inspiration foal wasn't actually Sea Star but the foal's memory lives on as Sea Star. Marguerite Henry did extensive research on the care of orphaned foals which she incorporated into the story. She inserted the Beebe family into the story for continuity, although they weren't involved with the colt. In some of her writings and letters to children she wrote as of Sea Star was real and thriving. Marguerite often softened the harder real life facts for her young fans in this manner. She also later wrote that she dreamed part of the story of Sea Star.

Breyer produced a model of Sea Star from 1980 to 1987. The sculptor Chris Hess used Wesley Dennis's illustrations from the book to sculpt Sea Star's model.