She is one of the important side characters aside from the movie's stars, Goofy and his son Max.
She meets Goofy when Max takes him to sign up for a college library card before ditching him, unknowingly allowing his father to get to know her better and became his girlfriend.
She was voiced by Bebe Neuwirth in the movie and she was the love interest of Goofy only in An Extremely Goofy Movie.
Sylvia appears to be a beautiful young female dog with a small snout and short lush red hair. Her most common seen outfit is a white button top with a black shirt, wearing a pair of red frame glasses over her dark green eyes.
Later on, when dancing with Goofy, she was seen wearing an 1970's inspired outfit, colored mostly green, complete with gold hoop earrings and a large red afro like hairstyle. She also has removed her glasses and has light purple eye liner on her eyelids.
While she is seen as the quiet and well mannered librarian of the college Max and Goofy attends, she is shown to be a fun loving and sweet woman on the outside, quickly revealed by Goofy upon meeting her.
She was a fan of old collectibles and loves to dance. Eventually, she falls in love with Goofy and is seen as his girlfriend after their first "date" together.
She is shown to have a cold side to her when Goofy accidentally forgot their date when he felt dishearted from Max rejecting him.
Since then, she remained cold and distant from Goofy when they met again, though this later faded away after Goofy pleaded for her help in improving his grades, and rekindling his relationship with his son.
She also values family bonds as she watches in hope at the changes transpiring between Max and Goofy throughout the movie.