Mejiro Palmer is an umamusume with brown hair with a thin white streak in her bangs. She wears her hair in a ponytail, and has a ring shaped sidelock on her right ear.

Her signature racewear consists a white cropped jacket, with a tan fur collar. Going down either sleeve is a green stripe. She wears a white glove on her left hand. Underneath her jacket is a simple yellow cropped tank top with a collar, and a golden necklace with a circular pendant at the end. She wears a dark green golf skirt with yellow pleats, and a white stripe along the trim. Tied in the belt loops is a magenta ribbon with purple and white stripes. She wears a simple pair of sneakers, the left being white with black laces, and the left being black with white laces.

She is a part of the Mejiro family, with her relatives being Mejiro McQueen, Mejiro Bright, Mejiro Ryan, Mejiro Dober, Mejiro Bright, and Mejiro Ramonu, and Palmer is the most casual member of the family.

Her best friend is Daitaku Helios, whom She's besties with and both are very very good Friends, and when they run together in races, they tend to usually run at the same pace in the front all the way until the end. Her roommate however, is Katsuragi Ace, whom she doesn't speak much with.