Furnishing novice school leaders with the knowledge and skills they require to be successful in practice has proved difficult. This paper describes and analyses an attempt to link learning and school leading practices in their education: a three-year learning activity within the Swedish National School Leadership Training Programme intended to develop novice school leaders' ability to analyse, critically examine, formulate and implement school improvement strategies. The theoretical point of departure is a social constructionist and situated perspective on learning. Drawing on data from 120 reports submitted by school leaders at the end of years two (n = 60) and three (n = 60) of the programme, and nine audio-recorded conversations between groups of the leaders, we identify critical aspects of the learning process. The findings indicate that the novice school leaders initially perceived the learning activity to be challenging, but it gradually became a mediational mean and boundary object in and between their practices. Critical elements for this were the activity's design and length, systematic approach, supportive tools and 'forcing moments'. We argue that linking training practice to school leading practice may have positive effects on novice school leaders' professional development.