In a historical perspective it is evident that Early Childhood Education and Care (ECEC) has made a crucial impact on Swedish society. The importance of the expansion of ECEC for the construction of the welfare state in Sweden is significant as it has influenced family and labour market policy, social equality and gender equality. In this chapter we describe the expansion of ECEC institutions in Sweden, mainly using two concepts for analysing workforce development: (a) the concept of professionalization processes; (b) the gender concept. The common feature for the two concepts is the power dimension. The expansion of ECEC institutions and the development of a workforce in ECEC has struggled for legitimization and cultural recognition in society. The struggle for professional legitimization and the resistance it met is obviously related to power relations, gender issues and the acceptance of a female labour force.