Teacher education instructions are undergoing significant pedagogical transformation amid global shifts toward hybrid learning environments. This empirical study investigates the differential impacts of blended learning-integrating online and offline instruction—on academic achievement, learner engagement, and professional competency development among teacher education trainees in colleges of education in Jamkhandi Taluk, Karnataka, India. A convergent mixed-methods design was employed with 312 trainees across four institutions. Quantitative data were gathered through pre-test/post-test instruments and standardized learning outcome evaluations (Cronbach's α = 0.847 and 0.812, respectively), while qualitative data were obtained through semi-structured interviews with 45 trainees and 16 faculty members. One-way ANOVA revealed statistically significant differences across instructional modalities: F (2, 309) = 23.54, p < .001, η² = 0.13 (large effect). Blended instruction yielded the highest post-test performance (M = 82.09, SD = 8.14), significantly outperforming offline (M = 79.02, SD = 8.48) and online-only modes (M = 73.88, SD = 9.58); Tukey HSD confirmed all pairwise differences (p < .05). Cohen's defect sizes were 0.92 (blended vs. online, large) and 0.37 (blended vs. offline, medium). Engagement scores mirrored this pattern: Blended (M = 4.2/5), Offline (M = 3.8/5), and Online (M = 3.1/5). Humanities trainees demonstrated greater achievement gains (8.7%) than STEM trainees (5.2%) in blended settings. Thematic analysis of interview data yielded seven themes: flexibility advantages, practical skill necessity, infrastructure challenges, faculty development needs, socialrelational value, subject-specific differences, and assessment alignment. Findings indicate that optimal learning outcomes in teacher education require contextualized, discipline-specific hybrid models rather than uniform single-modality implementation. Policy recommendations include a 60:40 blended instructional ratio, investment in offline laboratory infrastructure, and TPACK-focused faculty development with 80% institutional coverage.