The active participation of teachers in designing classroom learning experiences contributes to teacher abilities to facilitate learning. This paper reports on a case study of one Dutch teacher designing a technology-rich learning environment for emergent literacy. Data was collected to explore the design and implementation of the learning environment. The main findings from the design study are that scaffolding teacher design takes mammoth effort; appears to contribute to teacher learning; yields usable products and ownership, both of which seem to contribute to classroom implementation, but also yields products whose subject matter quality is questionable. The pre-post test data from the implementation study indicates that all children working with the intervention exhibited significant learning gains. Based on the findings, it is hypothesised that the high degree of teacher ownership which stems from designing classroom materials positively influences integration of on-computer activities with off-computer classroom activities, and that a high level of integration yields positive influence on pupil learning about the functions of written language. This rich but small-scale study points to the need for more refined understanding of the gap between what teachers have already mastered and what they can achieve when provided with support, when engaging in technology-rich classroom innovation. We therefore call for innovation design to not only meet learner needs, but also to fit explicitly within a teacher's "technological zone of proximal development". (Contains 1 table and 1 figure.)