The burden of chronic disease in Europe continues to grow. A major challenge facing national governments is how to tackle the risk factors of sedentary lifestyle, alcohol abuse, smoking, and unhealthy diet. These factors are complex and necessitate intersectoral collaboration to strengthen health promotion, counter-act the social determinants of health, and reduce the prevalence of chronic disease. European countries have diverse intersectoral collaboration to encourage health promotion activities. In the Joint Action CHRODIS-PLUS success factors for intersectoral collaboration within and outside healthcare which strengthen health promotion activities were identified with a mixed method design via a survey of 22 project partners in 14 countries and 2 workshops. In six semi-structured interviews, the mechanisms underlying these success factors were examined. These mechanisms can be very context-specific but do give more insight into how they can be replicated. In this paper, 20 health promotion interventions from national programs in CHRODIS PLUS are explored. This includes community interventions, policy actions, integrated approaches, capacity building, and training activities. The interventions involved collaboration across three to more than six sectors. The conclusion is a set of seven recommendations that are considered to be essential for fostering intersectoral collaboration to improve health-promoting activities.