Both parents and important non-parental adults have influential roles in promoting positive youth development (PYD). Little research, however, has examined the simultaneous effects of both parents and important non-parental adults for PYD. We assessed the relationships among youth-reported parenting profiles and important non-parental adult relationships in predicting the Five Cs of PYD (competence, confidence, connection, character, and caring) in four cross-sectional waves of data from the 4-H Study of PYD (Grade 9: N = 975, 61.1% female; Grade 10: N = 1,855, 63.4% female; Grade 11: N = 983, 67.9% female; Grade 12: N = 703, 69.3% female). The results indicated the existence of latent profiles of youth-reported parenting styles based on maternal warmth, parental school involvement, and parental monitoring that were consistent with previously identified profiles (authoritative, authoritarian, permissive, and uninvolved) as well as reflecting several novel profiles (highly involved, integrative, school-focused, controlling). Parenting profile membership predicted mean differences in the Five Cs at each wave, and also moderated the relationships between the presence of an important non-parental adult and the Five Cs. In general, authoritative and highly involved parenting predicted higher levels of PYD and a higher likelihood of being connected to an important non-parental adult. We discuss the implications of these findings for future research on adult influences of youth development and for programs that involve adults in attempts to promote PYD.