Walsh won three medals at the ICF Canoe Slalom World Championships with a silver (K1 team: 2009) and two individual bronzes (K1: 2006, 2007). He is the overall World Cup Champion in K1 from 2004. He is the 2008 individual European Champion, and the 2009 European Team Champion along with Richard Hounslow and Huw Swetnam. He also has 1 silver and 2 bronze medals from the European Championships.