Background: Uganda's introduction of the Competency-Based Curriculum in 2020 represented a paradigm shift toward holistic education emphasizing practical competencies beyond academic knowledge. However, the curriculum's effectiveness in developing essential 21st-century soft skills—particularly negotiation, lobbying, and interpersonal competencies critical for Ugandan youth's success in modern labor markets and civic participation— remained underexplored. Objective: This study critically analyzed Uganda's Competency-Based Curriculum to assess its effectiveness in developing negotiation, lobbying, and essential soft skills among Ugandan youth, specifically examining: (1) the extent of soft skills integration within the curriculum framework, (2) pedagogical approaches and resources employed by educators, and (3) gaps, challenges, and opportunities for strengthening skills development. Methods: A mixed-methods design was employed across 45 randomly selected secondary schools from five Ugandan regions, stratified by school type. The sample included 384 students (aged 15-19), 180 teachers, 45 head teachers, and 30 curriculum developers and policy stakeholders, calculated to achieve 80% statistical power. Data were collected through structured questionnaires, semi-structured interviews, focus group discussions, and document analysis of curriculum materials. Quantitative analysis employed descriptive statistics, chi-square tests, ANOVA, and multiple regression using SPSS version 26, while qualitative data were analyzed thematically using NVivo software with triangulation across data sources. Results: The study revealed that soft skills integration varied significantly by subject area (χ² = 18.47 to 48.93, p < 0.05), with Entrepreneurship Education (71.2%), Social Studies (67.8%), and Life Skills Education (64.5%) showing high explicit integration, while Mathematics (12.1%) and Sciences (18.4%) demonstrated minimal integration, yielding an overall explicit integration rate of 46.1%. Significant disparities existed across school types in pedagogical approaches and resource availability (F = 28.64, p < 0.001, η² = 0.243), with private schools (M = 3.90) substantially outperforming government (M = 2.81) and community schools (M = 2.47) in employing interactive teaching methods, accessing materials, and technology integration. Multiple regression analysis revealed that interactive pedagogies (β = 0.341, p < 0.001), teaching resources (β = 0.312, p < 0.001), and teacher training (β = 0.287, p < 0.001) were the strongest predictors of soft skills development, collectively explaining 56.0% of variance (R² = 0.560, F(7, 376) = 68.42, p < 0.001), while school type disparities persisted even after controlling for other factors (β = -0.178, p = 0.002). Conclusion: While Uganda's Competency-Based Curriculum incorporated soft skills development as a priority, implementation remained uneven, inequitable, and constrained by subject-specific biases, inadequate teacher preparation, insufficient resources, and significant disparities between private and public institutions. The curriculum's potential to develop negotiation, lobbying, and soft skills essential for 21st-century success was realized primarily in well-resourced private schools, while the majority of Ugandan youth in government and community schools received inadequate preparation in these critical competencies. Recommendations: The study recommended comprehensive integration of soft skills across all subject areas including STEM disciplines, large-scale teacher professional development programs emphasizing interactive pedagogies with targeted support for under-resourced schools, significant investment in educational resources with equitable distribution mechanisms, and establishment of robust monitoring and support systems to ensure implementation fidelity and address systemic challenges in curriculum delivery.