Sunny is a sunshine yellow Pegasus pony whose coat glitters in sunlight. Her mane is sunflower yellow and she has cadet blue eyes. Her cutie mark, located on her left flank, is a yellow sun with eight rays of light.
Sunny Shine was born in Cloudsdale, but she wanted to live in Ponyville, but her mom wouldn't let her in fear that Sunny would get hurt. Starting at the time she could walk, Sunny would fly around Cloudsdale, wrecking havoc wherever she went. Two years later, after the birth of Riptide and Downpour, Windy forced Sunny to stay inside of their home so her little brother and sister didn't obtain her reckless personality. As the colt and the filly grew older, Sunny had to babysit them, which caused her to become anti-social because she had no one her age to talk to. Over time, her mother had two more children, the playful Snowflake and the shy Mistveil. About six years later, when her father, Meteorite, died, Sunny's mother became extremely depressed. Sunny began to think about moving to Ponyville until her mother caught a dangerous sickness and became extremely weak. Sunny tried her best to be happy around her mother so she didn't cause her mother to become even more depressed. Sunny then decided to head to Ponyville to see if anyone there can cure her mother's sickness. There, she met Starshimmer, a budding magician who could use healing spells. Sunny then told Starshimmer to get on her back so she could carry her to Cloudsdale. Sunny rushed Starshimmer to her mother's hospital bed, where Starshimmer recited a spell she nicknamed "Starfall". To Sunny's prayers, her mother was healed. Because Sunny's mother was surprised that Sunny saved her, Windy allowed her daughter to resume her fun-loving ways and live in Ponyville.
Sunny is an extremely energetic. She is also extremely overconfident, which gets her into trouble often. Sunny is also an extremely loyal friend and likes to cheer others up, shown when Starshimmer is depressed and Sunny visits her.
Sunny respects Rarity because Rarity has helped Sunny create her own clothing and accessories.
Starshimmer and Sunny have been friends for a very long time. Eventually, Sunny developed feelings for Star, but she hides her affection because she's afraid that Star won't return the feelings.
- "Looks like somepony has anger issues." -Sunny talking about Lavaflow