Social determinants of health (SDoH) screening and intervention in primary care aim to alleviate adverse influences on health, but its efficacy may be diluted when offered supports are not well matched to families' desire for such services. The purpose of this prospective cohort study was to provide guidance to social care navigation teams regarding which families would be most likely to make use of services. Analysis of registry data collected in April 1-September 30, 2021 from a social care navigation program embedded in a medical home was conducted. Multivariable regression models explored (1) whether family-reported urgency of needs, number of needs, and/or specific types of needs predicted completing program intake and (2) whether the degree of family activation regarding social needs predicted subsequent interactions with the navigation team. Of the 1,483 families reporting any social care needs (38% of all screens completed, mean of 2.5 needs per screen), 31% indicated that their needs were urgent. Accounting for program factors and the number and type of needs reported, families whose needs were urgent were more likely to complete intake (OR=1.34; 95% CI=1.01, 1.82; p=0.04) and remain engaged with the program over time (OR=2.25; 95% CI=1.62, 3.12; p<0.01). Those who were self-advocates were substantially less likely to desire follow-up or stay engaged (OR=0.40; 95% CI=0.17, 0.93; p<0.01). Family-reported urgency of needs and activation for social care assistance predicted engagement with the navigation team. SDoH interventions should prioritize outreach to those families expressing an interest in help with any of their identified needs.