Purpose To compare Aevidum’s school mental health curriculum vs the curriculum plus Aevidum clubs in a mixed-methods study including pre/post surveys, a randomized clinical trial, and qualitative interviews. Design Concurrent mixed-methods: Aim 1) pre-post surveys evaluated curriculum only vs curriculum plus club schools separately regarding changes in knowledge, help-seeking, and school culture; Aim 2) randomized clinical trial compared curriculum only to curriculum plus club schools; Aim 3) qualitative school staff interviews enhanced understanding of school culture changes. Setting Curriculum delivered to 9th graders at ten Pennsylvania high schools; 5 schools randomized to start clubs. Subjects Students (surveys), staff (interviews). Intervention Aevidum curriculum plus/minus club. Measures Aim 1, mixed effects linear and logistic regression models for longitudinal data were used to analyze survey items at each time point. Aim 2, the same regression models were used, except models included a fixed-effect for group and group by time interaction effect. Aim 3, interviews were transcribed; a codebook was developed followed by thematic analysis. Results Pre-survey 2557 respondents; 49% female, 86% non-Hispanic white. Post-survey 737 (29% response rate). Aim 1, pre-post (Likert responses, larger numbers favorable) demonstrated increased student knowledge to identify depression (4.26 [4.19-4.33] to 4.59 [4.47-4.71], P < .001) and help a friend access support (4.30 [4.21-4.38] to 4.56 [4.40-4.71], P = .001). Help-seeking increased for phone helplines (1.61 [1.57-1.66] to 1.78 [1.70-1.86], P < .001), crisis textlines (1.60 [1.55-1.64] to 1.78 [1.70-1.86], P < .001), internet/websites (1.80 [1.75-1.85] to 1.99 [1.90-2.08], P < .001), school counselors ( P = .005) and teachers (.013). Aim 2, no significant differences in knowledge, help-seeking or culture between curriculum only vs curriculum plus club schools. Aim 3, staff (n = 17) interviews supported reduced stigma and increased mental health referrals. Conclusions Aevidum’s curriculum improved mental health knowledge and help-seeking; adding the club did not significantly change responses. Staff identified positive school culture impacts. Limitations include the lower post-survey response.