Research suggests that spousal communication and male involvement in decision making can positively influence family-planning use and continuation. However, few existing studies explore the dynamics of this communication and how they factor into family-planning decision making. Building upon a recent evaluation of a theory-based male-involvement intervention in Malawi, this study aimed to fill this gap by examining the role of communication in the intervention's success, through semi-structured in-depth interviews with male participants and female partners of study participants. Results support the idea that communication is an integral component of successful interventions to increase male involvement in family planning. Participants reported improvements in spousal communication, increased frequency of communication, and an increase in shared decision making as a result of the study, which directly contributed to their family-planning use. This effect was often mediated through increased knowledge or reduced male opposition to family planning. Further analysis of communication and decision-making dynamics revealed shifts in gendered communication norms, leading to improvements in spousal relationships in addition to contraceptive uptake. This study shows that interventions can and should encourage spousal communication and shared decision making, and it provides an effective model for involving men in family-planning use.