Walstad played in three World Junior Curling Championships, from 2008 to 2010 inclusive. At the 2008 World Junior Curling Championships he played third for the Kristian Rolvsfjord rink, finishing in 4th place. At the 2009 World Junior Curling Championships he played second for the team, finishing in 5th place. And at the 2010 World Junior Curling Championships, he played second for the Steffen Mellemseter, finishing 5th overall.