This study aimed to empirically examine performance characteristics of families participating in family-unit volunteer activities, focusing on the structural relationship and to obtain practical implications for creation of valuable performance and revitalization of family volunteering programs by additionally analyzing the moderating effects of service motivation, service period, and reward, which are manageable service characteristics. We conducted interviews with 308 families from 15 centers running family volunteering programs using structured questionnaires and based on the data collected, we examined the structural causal relation (among volunteer satisfaction,, family soundness, and family life satisfaction) and the moderating effects of service characteristics (motivation, period, and reward) through structural equation (including multi-group analysis). The study findings are as follows. First, there was a significant causal relation among volunteer satisfaction,, family soundness, and family life satisfaction. Second, volunteer satisfaction, (antecedent) specially had a significant relation with activity satisfaction and family soundness (mediator) specially had a significant relation with sharing of belief system and problem-solving capability. Third, among the service characteristics, only service period and reward were significant. These findings imply that on the assumption that service performance in family volunteer activities may lead to family performance, a systematic participating family-centered management system should be developed. This study, therefore, suggests a two tract approach, a pre-participant assessment post-program design strategy, and a systematic service period and reward connection strategy for improvement of service performance and family soundness.