This study analysed the influence on leadership behaviours acquired through a structured development programme. A total of 30 municipality workplaces around the west coast of Sweden participated in a leadership intervention using a case-control design. The oneyear programme included lectures, seminars, group and individual reflection, and for some participants, an intervention that included group development activities with subordinates. The intervention was based on the healthy and effective leadership (HEL) model. The model draws from common leadership behaviours in successful organisations. Among municipalities in western Sweden, does subordinate perception of their managers’ HEL behaviours differ between subordinates whose managers participated in one-year leadership development programs and subordinates whose managers were in a control group? The leadership development programme, both with and without a systematic group development process, had a significant positive relation with the change in the HEL behaviour index when controlled for age, gender and education compared with a control group from the same region and sector. Further research is suggested using longitudinal leadership behaviour intervention studies that focus on both subordinate health and organisational effectiveness.