This paper presents findings from a Swedish interview study from 2016-2017 with 20 professionals working with young people, who suffer from a combination of mental ill-health and social vulnerability. They have been recipients of long-term support from multiple welfare service actors with the aim of promoting the young people’s wellbeing. The aim of the study is to investigate professionals’ experiences of work practices aiming at increased wellbeing for this group of young people. Mental ill-health among young people has increased in the past decades in Sweden as well as in many other western countries. Mental ill-health has also been connected with social vulnerability such as difficulties in completing education, unemployment, out-of-home care or substance abuse. This group of young people are sometimes referred to as youth with complex needs. Complex needs is a concept used to categorize people that have multiple interconnected needs that span medical and social issues, people that are considered as especially disadvantaged, or presenting challenges to welfare services. Categorizations of people and needs are prerequisites for legal, bureaucratic and professional systems within the welfare state. Welfare organizations construct knowledge and strategies regarding specific target groups according to these categorizations. In the paper we argue that the expression complex needs, when used as a way to categorize young people, not necessarily take into consideration that the problem instead may be the complex organizations that young people meet. These organizations may not always succeed in catering for the needs of young people.