Semyon Varlamov made 28 saves for the Islanders (16-17-6), who have lost three of their past four games and were shut out for the fourth time at home this season.
After playing 14 of its past 15 games at home, New York will play nine of its next 11 on the road.
"To me, it's one of the more disappointing games that I've coached as an Islander coach, to be honest with you," Islanders coach Barry Trotz said. "It was quite disappointing. We've had some games where we've got taken apart by a really good hockey team, but the effort's there, maybe we made some mistakes, but I just didn't think that our level of desire today was very good.
"I'm [ticked] off right now, plain and simple, and I'll let the emotion hopefully go away. I'll reassess our team. We're going to need more. We're going on the road, playing good teams and we've got to put in a better effort. We've had some great efforts and we didn't get a win. I thought we had a really good effort obviously against Minnesota (a 4-3 loss on Sunday), but we didn't get any points. But this one, we didn't deserve any points. If we would've, we would've stole it."
McCann gave the Kraken a 1-0 lead at 6:04 of the third period. Jordan Eberle outmuscled Scott Mayfield for the puck behind the net and sent a pass to McCann, who quickly shot off the left arm of Varlamov for his team-leading 19th goal of the season.
"I just feel like things this year are going well and I'm getting put into good situations to score," McCann said. "I'm just trying to take advantage of it. Obviously, I'm playing with two great players (Eberle, Marcus Johansson), and obviously, that helps a lot, too."