On 4 August 2015, he signed with Seattle Sounders FC in Major League Soccer. After suffering from an injury his debut was postponed to 13 September where he assisted a late Obafemi Martins goal to tie up the game against San Jose Earthquakes. Ivanschitz converted Seattle's second kick from the spot in the 2016 MLS Cup penalty shootout, which the Sounders eventually won after six rounds, securing their first MLS Cup Title.