The concept of integrated services is a common feature of current social policy discussions. It is often argued that social support systems have not evolved to cope with the complexity of individuals’ needs. This is deemed true for a variety of interrelated difficulties that cut across traditional welfare programmes and life course lines. This article examines the efforts of integrated services to bridge policy areas such as social policy, labour market policy and health care services for four different vulnerable groups at major stages of the life course: childhood, youth, adulthood and old age. Analytically, the article adopts a framework developed by Valentijn et al. (2013) that allows systematic comparisons. Using mainly high-income economy examples, the article connects key features of a certain policy area with key elements of integrated services. Key features of a policy area direct attention to the function of the policy area, and these are expressed through the framework of “person-focused” and “population-focused” services. Key elements of integrated services in turn emphasize levels of integration (macro, meso, micro). Central questions addressed are the character of integration efforts for vulnerable groups at different stages of the life cycle and how variations therein can be understood. As a complement, sociological explanations of individual vulnerability, which are separated by causes of vulnerability into basic, conditional and triggering factors, are also used. A main finding is that the life course perspective as such does not explain variation in integration efforts; rather, it is the institutional features of the specific policy areas. These constrain or promote the potential for greater integration.