Little My lives with her sister Mymble at the Mymble Residence. Before the series began, she spent winters hibernating at Moominhouse. She awakens when Moomintroll announces spring, immediately confronting him for interrupting her dream about living inside a watermelon. Reminded she asked for the wake-up call, she declares hunger and demands watermelon from Moominmamma, settling for another breakfast when told it's unavailable.

She expresses skepticism openly, like doubting the Snork's flying ship project. During games, she hides effectively, once inside a kitchen pot to surprise seekers. She displays competitiveness, instigating and winning cloud-riding collisions against Sniff, showing disappointment when weather ruins play.

Physically small with red hair in a ponytail, she wears a simple red skirt. Her personality is mischievous, spiteful, and fearless. She speaks bluntly, often rudely, but maintains friendships. She acts aggressively and seeks immediate action when wanting something. She accompanies Moomintroll to meet Snufkin but leaves early to check on Mymble's return instead of staying.

She is Mymble's younger sister. In this adaptation, unlike the original books, she has no familial connection to Snufkin. Episodes depict her romantic interest in him. Her background lacks detail on birth origins or extended family beyond living with Mymble.

Key moments include her witnessing Moomintroll's transformation by the magic hat and seeing Moominmamma recognize him despite his altered appearance. She joins group investigations into strange events but avoids direct involvement in solving them. Her role remains consistent as an observer and commentator on others' actions, not driving major plots. Her character shows minimal evolution across episodes, maintaining established independence and sarcasm.