As an 18-year-old in 2006, he became the youngest to play for Sweden at the World Championship, playing on the top line with Henrik Zetterberg and Johan Franzen. He won gold, playing the last four games of the tournament, filling a spot previously held for Daniel Alfredsson.
Playing in his home country at the 2007 World Junior Championships, Backstrom led his team and finished second behind Patrick Kane with seven assists for the tournament.
He played alongside fellow 2010 Olympian Patric Hornqvist at the 2008 World Championships and together they combined for 13 points (9-4-13). Sweden lost to Finland in the bronze medal game.
That was something I've been dreaming of, something I've told myself before the third period I was going to do ... It was an amazing feeling. It's hard to describe. I didn't believe it went in at first but when I saw all the reaction and all the fans going crazy and my teammates going crazy, it's just an unbelievable feeling. I didn't know what to do. I didn't know whether to jump or just skate and do a Theo Fleury. I don't think I'm the same caliber player he is so I couldn't do it.
— Flames forward Mikael Backlund on scoring the overtime winner against the Ducks in Gm. 3