Arnaldur has a PhD in economics from the University of Oslo and is currently an assistant professor in economics at the University of Iceland. He previously worked at the Social Research Center at the University of Iceland, the Norwegian Ministry of Finance, and the Icelandic Confederation of Labour. His research has focused on income distribution, the effects of tax-transfer systems on income distribution, and optimal taxation of labor and capital income. His current research projects are on intergenerational mobility, optimal taxation, and automatic stabilization.