BackgroundEarly sleep problems co-occur with crying, eating problems, and parental distress. This study investigates the impact of a parent-focused intervention to improve child sleep with the following aims: (1) To assess the impact on child sleep (sleep onset latency, frequency and duration of nighttime awakenings, frequency of bed-sharing, and nighttime food intake, total nighttime sleep duration, and sleep efficiency), child crying (frequency of crying episodes, of unexplained and unsoothable crying and of crying out of defiance), child eating difficulties, and parental distress of mothers and fathers. (2) To assess the maintenance of any changes in these areas longitudinally, at 3-month, 6-month, and 12-month follow-ups. (3) To explore at the within-subjects level, how children’s sleep, crying, eating, and parental distress changed together across all study measurement points.MethodsIn this single-arm pilot study, the parents of 60 children participated in six individual sessions of a parent-focused multimodal age-adjusted cognitive-behavioral intervention to improve child sleep. Parents of 39 children (46% girls, age in months M = 22.41, SD = 12.43) completed pre- and at least one measure after the intervention. Sleep diary, questionnaire for crying, feeding, sleeping, and parental stress index (short-form) were assessed pre, post, three, six, and 12 months after the intervention.ResultsSignificantly, sleep (decreased sleep onset latency, frequency, duration of nighttime awakenings, bed-sharing, nighttime food intake; increased total nighttime sleep duration, sleep efficiency), crying (reduced frequency of crying episodes, unexplained and unsoothable crying), and parental distress (reduced) changed, which remained partially stable over follow-up. The frequency of crying episodes decreased with fewer nighttime awakenings; morning crying with increased nighttime feeding; unexplained and unsoothable crying with higher sleep efficiency; crying due to defiance with more nighttime awakenings, sleep efficiency, and bed-sharing. Eating problems decreased with shorter night awakenings and time; maternal distress with fewer nighttime awakenings, paternal with less child’s nighttime feeding, unexplained and unsoothable crying, and time.ConclusionsA parental sleep intervention for sleep-disturbed young children could be promising to reduce children’s sleep problems, crying, eating problems and parental distress. Future studies should consider more personal contact during the follow-up to reduce the drop-out rate and a randomized-controlled design.Trial registrationThe study was retrospectively registered at the German Clinical Trials Register (ID: DRKS00028578, registration date: 21.03.2022).