While existing research has established the influence of digital technology use, flow, and learning engagement on students' subjective well-being, there remains a gap in understanding the interrelationships among these factors and the serial mediating role of flow and learning engagement in the relationship between digital technology use and adolescents' subjective well-being. This study examined the potential indirect roles of flow and learning engagement in the association between digital technology use and adolescents' subjective well-being. A paper-based survey was conducted among 1289 adolescents (M = 16.33, SD = 1.688) in Shandong Province. All participants completed a structured self-report questionnaire, including measures of digital technology use, flow, learning engagement, and subjective well-being. Data analyses were conducted using structural equation modeling via Amos 24.0 and SPSS 24.0. The results are as follows: (1) digital technology use has a significant and positive effect on adolescents' subjective well-being; (2) digital technology use significantly and positively affects adolescents' subjective well-being through flow; (3) digital technology use significantly and positively affects adolescents' subjective well-being through learning engagement; (4) digital technology use significantly and positively affects the subjective well-being of adolescents through both flow and learning engagement. This study underscores the benefits of digital technology in boosting adolescents' well-being and identifies flow and learning engagement as key mediators. Our findings equip educators and policymakers with insights to craft interventions that optimize digital technology's role in fostering adolescent development, presenting a fresh view on the intricate dynamics linking digital interaction with psychological health.