Rosanne Sorrentino was born on January 15, 1968, in Oceanside, Long Island, New York. She made her professional stage debut in the 3rd National Tour of Annie in 1980-81, playing the title role of Annie.
Sorrentino was "bitten by the acting bug" in 1976, when she played a schoolgirl in the American Academy of Dramatic Arts's summer workshop production of The Prime of Miss Jean Brodie. The play was written by Jay Presson Allen, the wife of Lewis Allen, one of Annie's producers. Rosanne was also a member of her school chorus at Lindenhurst Senior High School and it was under the direction of her school music teacher, Liz Costa, that she developed her love for singing. She was also involved with the Charles Street Players in Lindenhurst High School. Her greatest role being that of Grizabella in their rendition of Cats.Although Sorrentino received critical acclaim for her stage portrayal of Annie, she was considered too old - at the age of 13 - to be cast as Annie in the film version. Instead, after auditioning, she was offered, and accepted, the role of Pepper - the oldest, and bossiest, orphan.