Eileen is a 3'6" mole girl in her early 20s with tan fur. However, her appearance is very humanoid, excluding her toes and tail, which don't resemble that of a mole's either. She wears red round glasses and has two eyelashes on each of her eyes. Without her glasses, her eyes are just two black dots with eyelashes.

Her most common outfit outside of work, especially in Season 8, is a pink t-shirt and blue jeans with the cuffs rolled up.