Sour has a pale, light grayish gold skin tone, she has a long moderate rose with lighter moderate rose and grayish aquamarine streaks tied in a high ponytail, she has moderate indigo eyes and has freckles on her face. She wears a purple buttoned vest over a blue short-sleeved shirt with a black ribbon tie, a dark purple plaid skirt, dark-purple frilled high socks and black leather shoes. True to her name, Sour Sweet has somewhat of a bipolar personality where she alternates between being sarcastic and rude (sour) and obnoxiously nice (sweet). This trait is more subdued in her later appearances.

She acts mean towards Twilight throughout Friendship Games, irritated by her thoughtless and clumsy behavior, which she believes will cost her team's victory in the games. Much like the rest of her school, Sour Sweet is highly competitive and confident in her athletic skill, and she is willing to use peer pressure against Twilight to manipulate her into using magic for Crystal Prep's benefit. After this ends up endangering both schools, Sour Sweet becomes remorseful and helps rescue her classmates alongside Canterlot High's students.

In Dance Magic, Sour Sweet is initially conniving and deceitful, demonstrated when she steals Rarity's video idea for the contest. Her reasons for doing so, however, indicate that she cares about her Crystal Prep friends and classmates, and she shows a much friendlier side toward the Rainbooms in the end, especially with Rarity. you were entering school until she pinned you to the wall and started to flirt with you: hey there handsome.