The 39-year-old Juventus goalkeeper, who made his Italy debut in October 1997, kept a clean sheet against Sweden at San Siro but his teammates failed to score the goals to overturn the Scandinavians’ 1-0 advantage in the two-legged European zone playoff.
In tweets from the national team’s official account, he said: “We are proud, we are strong, we are stubborn.
“We will pick ourselves up as we have always done.
“I am leaving a national team set-up that will know how to pick itself up again.
“Best wishes to everybody, and especially to those with whom I have shared this beautiful journey.”
It was the first time since 1958 the four-time champions have failed to qualify for the World Cup.
The Swedes prevailed 1-0 on aggregate after they won the first leg on Thursday in Solna, and advanced to their first World Cup since 2006.
It could have been worse for Italy, as Sweden were denied what looked like two clear-cut penalties for handballs, first by Matteo Darmian and then Andrea Barzagli.
Italy had a penalty appeal of their own waved off when Marco Parolo was tripped from behind by Ludwig Augsustinsson.
But the Azzurri struggled to carve out clear chances against a solid Sweden side, and genuinely tested goalkeeper Robin Olsen only once.
This will be just the second World Cup Italy have failed to qualify for and the first in 60 years.
The last major competition Italy failed to qualify for were the 1984 and 1992 European championships.
The San Siro match also marked the end of Gianluigi Buffon’s 175-cap international career, with the 39-year-old announcing his retirement in the aftermath.
Jorginho created Italy’s best opportunities with two through-balls for Ciro Immobile, who hit the netting from a tight angle from one.
Immbobile beat Olsen with another but Andreas Granqvist got back for a decisive goalline clearance.
Alessandro Florenzi was back after a year out after twice tearing a knee ligament, and the midfielder forced Olsen into his only real save, while a cross of his was deflected onto the crossbar in the second half.
Italy’s players collapsed onto the pitch in despair as the final whistle went and veterans such as Giorgio Chiellini were inconsolable.
The crowd’s support during the game quickly turned to hostility as boos rang around the stadium.
Buffon had already decided to hang up his Azzurri gloves after Russia 2018 and, with that opportunity stripped from him seven months before the tournament, he is taking his leave early.
“The blame is divided equally among all of us,” he said.
“There must be no scapegoats.
“We win together and we lose together.
“I’m not feeling sorry for myself but I’m sorry about the whole affair.
“We blew something that could have meant so much. The main regret is that it ended like this.”