Born in Irvine, North Ayrshire, Mundell was educated at Moffat Academy and graduated with a first-class Bachelor of Laws from the University of Edinburgh. He was first elected in the 2016 Scottish Parliament election and shortly after was made Scottish Conservative spokesperson for community safety. In the 2016 European Union membership referendum, he campaigned to leave the EU, stating he believed Scotland did not receive a good deal from the Common Agricultural Policy.