The Mamma Mia program is an internet-based intervention designed to prevent and/or intervene with perinatal mental health symptoms, such as depression symptoms. The purpose of this mixed-methods study, which occurred in a virtual setting, was to evaluate the perceived acceptability, obtrusiveness, and preliminary perceived usefulness of the Mamma Mia program by postpartum mothers who had access to the program through a larger parent study. Quantitative data on perceived obtrusiveness of the program (Unobtrusiveness Scale) were collected from 1772 pregnant women participating in a larger, three-arm randomized controlled parent study (clinicaltrials.gov: NCT04300894); qualitative data were obtained through semi-structured one-on-one interviews with a subset of these postpartum mothers (n = 55). Participants reported they found the program to be beneficial, emphasizing its guided content, focus on self-care, integration of mindfulness and educational components, and trustworthiness. Participants appreciated the structured nature of the program and expressed a high level of trust in the program, which was crucial for its perceived value and effectiveness. However, reported obtrusiveness of the intervention increased as participants progressed through the postpartum period, suggesting an evolving user experience with the program. Participants offered suggestions for improvement to the program, such as that the program should be app-based, the program should be available for partners to use, and that the program requires some updates to images and postpartum content. Overall, the study findings highlight the participants’ perceptions that the program is acceptable and useful. Future work is warranted to explore the enhancements proposed by participants to further optimize the program’s impact.