Sundstrom was drafted 50th overall in the 2011 draft by the Islanders. He has spent the previous three seasons playing in the AHL with the Bridgeport Sound Tigers. He also appeared in 11 games with the Islanders during the 2013-14 season. In 72 games this year, he recorded seven goals and 12 assists for 19 points. During the 2013-14 season Sundstrom scored eight goals and 10 assists for 18 points in 40 games.
His best statistical year came during his first pro season in North American when he put up 32 points (11 goals, 21 assists) in 59 games.
Sundstrom, 22, went through Frolunda's youth system and appeared in 49 games for the club during the 2011-12 campaign. The Islanders drafted the Swedish forward 50th overall in the 2011 NHL Draft.