Prevalence of mental health needs, particularly those related to anxiety, depression, and emotion regulation, are on the rise in higher education institutions (Auerbach et al., 2016; Blanco et al., 2008). Research has shown college and university student help-seeking behavior varies by identity and many students are often reluctant to seek support (Oswalt et al., 2020; Rickwood et al., 2007), and yet, there are increasing rates of students seeking counseling supports on college and university campuses (Abrams, 2020; Prince, 2015; Son et al., 2020; Xiao et al., 2017). To support students' mental health needs, creative, preventive mental health care is needed in higher education institutions. The present study is situated within the context of a preventive mental health care intervention for undergraduate students in the form of an optional, universally offered course. The course draws on principles of Dialectical Behavioral Therapy, Acceptance-Commitment Therapy, and Positive Psychology. In order to track intervention efficacy and support generalization and rehearsal of learned skills, students are tasked with using a self-monitoring tool called a diary card. Behavior change literature suggests that self-monitoring is a key factor in goal attainment and can even promote better intervention outcomes (Harkin et al., 2016; Kruglanski et al., 2002). Effective self-monitoring is that which is completed with fidelity, meaning high accuracy and consistency, both of which stand to be improved by technology. Digital formats of self-monitoring are increasingly popular because of their implications for self-monitoring fidelity and social acceptability (Aguilera, 2015; Avina, 2008; Cristol, 2018; Bedesem, 2012; Borntrager & Lyon, 2015; Dennison et al., 2013; Marzano et al., 2015; Melbye et al., 2020; Murnane et al., 2016; Sin et al., 2020; Ysseldyke et al., 2006). However, there remains a lack of robust evidence to support the use of digital self-monitoring tools in mental health interventions. This study adds to existing literature by using quantitative and qualitative methods to further explore the efficacy and social acceptability of a digital diary card used within a preventive mental health course at the university level. Students enrolled in the course were randomly assigned either to the Business as Usual (BAU) paper diary card or the digitally formatted diary card. Multiple regression analysis showed the digital diary card format uniquely predicted lower completion fidelity and social acceptability. Qualitative interviews further revealed students had difficulty with using and submitting the digital diary card, but even in spite of these challenges, would prefer a digital diary card in the future, emphasizing the importance of ease of use and submission in future designs. This paper concludes with recommendations for the design and implementation of a digital self-monitoring tool and directions for future research. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]