Bäckström played his first game with Sweden on 6 April 2006, in a game against Norway. He won the World Championship when he represented Sweden in the 2006 World Championship. As of that tournament, he is the youngest Swedish player ever in an Ice Hockey World Championship tournament. Bäckström played the last four games in the World Championship (roster spot held open for Daniel Alfredsson) and was directly appointed to the first line together with idols Henrik Zetterberg and Johan Franzén.