The fertility policy liberalization in China has meant that many firstborn children are stressed by a newborn sibling's arrival. This case study explores creative arts intervention as an innovative stress management approach to alleviate a Chinese girl's maladaptive reactions during her transition to siblinghood. A weekly 17-session tailored creative arts program used diverse art forms for self-exploration, emotion regulation, and family dynamics reconstruction in stages. The study employed an AB single-case design and utilized a mixed-methods approach for data collection. The results demonstrated that the child's maladjustment appeared closely tied to the cultural context of Chinese families. Creative arts intervention effectively improved the child's emotion regulation, family involvement, and social confidence as well as sibling warmth and managing jealousy. This case offers culturally situated insights to guide future child-centred, arts-based transition support research in Chinese families undergoing rapid structural shifts.