Cognitive learning theory suggests that linking familiar images with written language can help beginners connect meaning, print, and sound. However, evidence of improved reading scores offers limited explanation of how picture-word cards function alongside prior reading knowledge and instructional support. This study examined early reading outcomes following picture word card instruction among Grade I students at a public elementary school in South Tangerang, Indonesia. An explanatory sequential mixed methods framework guided a quasi-experimental comparison involving 68 purposively selected students, with 34 in each group. Pre-tests and post-tests were administered before and after four instructional sessions, and quantitative findings informed the development of a follow-up semi-structured interview guide for one teacher. Descriptive statistics and analysis of covariance were used to compare reading performance while accounting for initial scores. The experimental group’s mean increased from 60.0 to 80.4, compared with 64.4 to 72.5 in the control group. ANCOVA indicated a significant group difference after pre-test adjustment, F(1, 65) = 39.4, p < .001, partial η² = .377. Initial reading performance also remained strongly associated with post-test achievement. These findings support a short-term advantage for the instructional approach as implemented, while leaving its cognitive mechanisms and the separate contribution of pictures unresolved. The study suggests using picture word cards with explicit attention to letter–sound relationships, guided practice, and support responsive to students’ starting ability. Evidence from one school and four intervention sessions warrants cautious application in similar classroom contexts, and future research should examine retention and independent reading over longer periods