Scrum methodology is a novel framework for teaching intended to scaffold students' learning process when they work on complex, real-world tasks. It is originally a project management framework frequently used in business and industry to manage projects. Scrum methodology is increasingly used in educational contexts. Yet, it is also a rather complex framework and more insight in how teachers understand and implement Scrum methodology is needed. Twelve teachers attended a professional development program and simultaneously implemented Scrum methodology in their chemistry lessons. Teachers' didactical expertise and pedagogical expertise appeared to play a key role during the implementation process, whereas teachers' subject matter expertise, and other factors such as teaching context, teaching experience and personal biography seemed to be less important. Didactical and pedagogical expertise enhances teaching with Scrum: it supports the implementation as well as increases its effectiveness, independently of teaching context, experience and personal biography. This would mean Scrum methodology offers possibilities for teachers to enhance and enrich their teaching practice.