Played by Diane Civita
When Arleen turns 16, her father reveals himself as a supreme chauvinist. He sends Arleen to a boarding school in Connecticut to learn how to become a lady. After boarding school, there comes College, Graduate School, then an unbearable job as a research assistant in a law firm.
After ten years' subservience, Arleen finally finds the courage to stand up against her father in 1976. Her father is then Commissioner Hart of the Santa Regina Police Department. Arleen tells him that she would like to be a cop. Commissioner Hart hits the ceiling, and wouldn't even talk to the recruiting investigators for Arleen. Arleen has got a few friends in the records department who helps her out. She enrolls on her own behind his back as an Arleen Smith.
When Jaime Sommers becomes a police cadet to investigate a foreign operative having joined the police academy, Arleen becomes her roommate and one of her best friends in the academy. She also impresses both her instructors and Jaime with her photographic memory, though Jaime initially suspects her of being an enemy infiltrator, when in fact Arleen's nocturnal excursions end up being more of the "midnight snack" variety.