This study examined how sociodemographic characteristics and histories of after-school programs—Hagwon—(학원)—relate to self-efficacy, behavioral adjustment, and academic performance among engineering students at Inha University in South Korea. Using a quantitative design and self-constructed Likert-type measures, 332 students (mean age 25.44; 53.3% male) reported their Hagwon participation and psychosocial and academic outcomes. Most respondents had long-term Hagwon attendance (five years or more) and commonly studied academic tutoring and foreign languages. Self-efficacy and behavioral adjustment were high, and academic records were generally strong; however, perceived academic achievement and participation/attendance were moderate. Age and higher year level were associated with lower self-efficacy and adjustment, while gender differences were observed across several outcomes. Hagwon length and subject type showed no meaningful associations. Findings highlight transition-sensitive and equity-focused supports to sustain confidence and adjustment under increasing collegiate demands.