In the 2006 election Federley was elected a member of the Riksdag for the Stockholm Municipality constituency, along with the actress Solveig Ternström. He was a member of the Riksdag's Committee on Social Insurance and the Swedish delegation to the Parliamentary Assembly of the Organization for Security and Co-operation in Europe (OSCE), and a substitute to the Committee on European Union Affairs. He was re-elected in the 2010 election.