Aquino was born in Teaneck, New Jersey, to Adele Frances (née Mesiti) and Salvatore Aquino. She first acted in junior high school productions. At Harvard University she was pre-med, majoring in biology. In her final year, she realised she was spending more time acting than studying and so left to travel to New York to take acting classes, while working at a law firm. She stayed there for three years without landing any acting jobs, before traveling on a recommendation to Minneapolis, where she gained her first roles. In 1986, after two years of rejections, she enrolled at Yale University School of Drama, where she studied three years.