Background: This paper describes the first phase of a community-based, controlled trial conducted to investigate the potential utility of a new, complex group-based early parenting intervention. In total, 106 parent-infant dyads were recruited to an interagency Parent and Infant (PIN) intervention which combines a range of supports, including the Incredible Years Parent and Baby Programme, baby massage, weaning workshops and paediatric first aid training. A ‘services-as-usual’ comparison group was also recruited (n = 84). Methods: The primary outcome was parenting self-efficacy (Parenting Sense of Competence Scale). Parent well-being, child development and the home environment were also measured. Assessments were conducted at baseline (when infants were 6–20 weeks old) and at follow-up (when infants were aged approximately 8 months). Parent satisfaction with the intervention was examined, as well as uptake of community-based services and health service utilisation. Results: An intention-to-treat analysis of covariance (ANCOVA) examined between-group post-intervention differences, whilst secondary analyses on a ‘per protocol’ sample of participants (who attended at least 50% of the intervention sessions) were also conducted. Satisfaction with the PIN intervention was very high. The intention-to-treat ANCOVA showed no post-intervention between-group differences on measures of parent competency or well-being. At baseline, children in the comparison group were older than those in the intervention group and, at follow-up, fared better than their intervention group counterparts on measures of child development. The per protocol analysis revealed a significant effect for the intervention group on the efficacy subscale of the primary outcome measure (effect size = 0.44, p < 0.05). Intervention group infants attended GP and nursing services on significantly fewer occasions than their comparison group counterparts. Conclusion: The findings provide tentative early support for the utility of the PIN intervention in terms of improving parenting efficacy and reducing reliance on primary health care services. Further follow-ups when infants are 16 and 24 months old are underway.