ObjectivesWe aimed to assess the effects of rooming‐in kangaroo mother care (KMC) on the breastfeeding and behavioral status of full‐term newborns.Materials and methodsFull‐term newborns born from June to December 2021 were divided into Group A (n = 50) and Group B (n = 50) using a random number table. The rooming‐in routine nursing intervention and KMC were given to Group A (n = 50) and Group B, respectively. The outcomes were compared.ResultsThe scores of breastfeeding knowledge, breastfeeding skills, and sense of responsibility for breastfeeding of Group B were higher than those of Group A (p < 0.05). The breastfeeding rate and lactation yield within 3 days of Group B were higher than those of Group A (p < 0.05). Compared with Group A, Group B had higher effective sucking times of newborns and lower behavioral status scores 1, 2, and 3 days after birth, and shorter duration of crying after invasive operation (p < 0.05). The newborns in Group B had better sleep quality, longer sleep time, and lower procedural pain score than those of Group A (p < 0.05).ConclusionRooming‐in KMC improves the maternal breastfeeding self‐efficacy, breastfeeding rate, and lactation yield, ameliorates the behavioral status and sleep quality of newborns, shortens the crying time and relieves the procedural pain.