The Better Start Literacy Approach (BSLA) is a strengths-based approach to supporting children’s literacy learning in their first year of school. Previous research has shown the approach is effective at accelerating foundational literacy knowledge in children with lower levels of oral language. This study examined the impact of the BSLA for children with varied language profiles and across schools from diverse socioeconomic communities. Additionally, a controlled analysis of the impact of Tier 2 teaching within a response to teaching framework was undertaken. Participants included 402 five-year-old children from 14 schools in New Zealand. A randomised delayed treatment design was utilised to establish the effect of Tier 1 teaching. Analyses showed a significant Tier 1 intervention effect for phoneme awareness, letter-sound knowledge, non-word reading and non-word spelling. There was no difference in intervention effects across socioeconomic groupings. Children were identified for Tier 2 teaching after 10 weeks of Tier 1 implementation. The progress of 98 children in response to Tier 2 teaching was compared to 26 children who met Tier 2 criteria but received only Tier 1 teaching within this study. Children in the Tier 2 group scored significantly higher on phonological awareness, non-word reading, and spelling than the control group at the post-Tier 2 assessment point, after controlling for pre-Tier 2 scores. The results suggest that a proactive strengths-based approach to supporting foundational literacy learning in children’s first year of school benefits all learners. The findings have important implications for early provision of literacy learning support in order to reduce current inequities in literacy outcomes.