"At this moment I can't believe it. It's really very wonderful," Munro told The Canadian Press in a telephone interview from Victoria just moments after the announcement was made in Stockholm.
"I knew I was in the running, yes, but I never thought I would win."
She added that she was delighted and "just terribly surprised."
In making the announcement, the Swedish Academy lauded the 82-year-old as a "master of the contemporary short story." Munro becomes the 110th Nobel laureate in literature and only the 13th woman to receive the distinction.
Soon after the news broke, media outlets around the world began clamouring to speak with the media-shy Munro. The author granted only a handful of interviews before her publisher, Random House of Canada, issued a statement saying she was "dazed by all the attention and affection" and would be saying nothing further.
Photographers, meanwhile, were asked to leave the hotel where Munro was staying, apparently at the request of the author.
Regarded as the world's highest literary honour, the Nobel puts Munro in the company of great wordsmiths including George Bernard Shaw, Ernest Hemingway, Hermann Hesse, T.S. Eliot and Toni Morrison. Canadian-born, American-raised writer Saul Bellow won in 1976.
While the esteemed prize is certainly the highest peak of the literary award landscape, Munro is no stranger to accolades.
She has previously won the Man Booker International Prize for her entire body of work, as well as two Scotiabank Giller Prizes (for 1998's "The Love of a Good Woman" and 2004's "Runaway"), three Governor General's Literary Awards (for her 1968 debut "Dance of the Happy Shades," 1978's "Who Do You Think You Are?" and 1986's "The Progress of Love"), the Commonwealth Writers' Prize, the inaugural Marian Engel Award and the American National Book Critics Circle Award.
When she won the Man Booker International in 2009, prize judge chair Jane Smiley noted that: "the surface of Alice Munro's works, its simplicity and quiet appearance, is a deceptive thing, that beneath that surface is a store of insight, a body of observation, and a world of wisdom that is close to addictive."
She had been considered a perennial contender for the Nobel, with British-based betting company Ladbrokes positioning her as the second-most likely recipient this year behind Japanese master Haruki Murakami. The prize money fluctuates, but last year's Nobel was worth roughly C$1.3 million.
The award will no doubt introduce legions of new readers to Munro's exquisite portraits of quiet moments and small-town life.
Reaction to those who have been touched by her work was swift and rapturous.
Ontario Premier Kathleen Wynne cited Munro's "Lives of Girls and Women" as a favourite, adding she is "part of a lucky population who has been forever changed by (Munro's) unparalleled ability to articulate the complexity and heartbreaks of everyday life."
McClelland and Stewart publisher Ellen Seligman called the Nobel a "momentous day for Canada and Canadian writing, and a thrilling honour in recognition of the extraordinary and enduring talent of Alice Munro, one of the great writers of our time."
Prime Minister Stephen Harper congratulated Munro on behalf of the entire country.
"Canadians are enormously proud of this remarkable accomplishment, which is the culmination of a lifetime of brilliant writing," he said in a statement.
"Ms. Munro is a giant in Canadian literature and this Nobel Prize further solidifies Canada's place among the ranks of countries with the best writers in the world."
Said NDP Leader Thomas Mulcair: "Munro's richly evocative short stories have helped tell Canada's story — both to Canadians and to others around the world."
The author's recent works include the 2009 collection "Too Much Happiness," which was nominated for the Governor General's Literary Award and a Writers' Trust Award, and 2012's "Dear Life," which won Munro her third Trillium Book Award.
Born in 1931 in the southwestern Ontario farming community of Wingham, Munro later moved to Victoria with her first husband, with whom she had three children.
The couple eventually divorced and Munro moved back to Ontario. She eventually remarried Gerald Fremlin, who died earlier this year.
Literary colleagues have long lavished praise on the author. Fellow short story writer Cynthia Ozick has called Munro "our Chekhov."
American novelist Jonathan Franzen has said she is the "remote provider of intensely pleasurable private experiences."
He has also said: "This is not a golfer on a practice tee. This is a gymnast in a plain black leotard, alone on a bare floor, outperforming all the novelists with their flashy costumes and whips and elephants and tigers."
Of her own work, Munro has said: "I want to tell a story, in the old-fashioned way — what happens to somebody — but I want that 'what happens' to be delivered with quite a bit of interruption, turnarounds, and strangeness. I want the reader to feel something is astonishing — not the 'what happens' but the way everything happens. These long short story fictions do that best, for me."
Three years ago, in an interview at Toronto's International Festival of Authors, Munro revealed she'd been through a battle with cancer but did not provide specifics.
And this past June, she told the National Post she was "probably not going to write anymore."
But in an interview posted Thursday afternoon on the Nobel Prize website, Munro suggested there may be more stories ahead.
"I've been doing it for so many years. I've been writing and publishing I think since I was about 20," she said.
"That's a long time to be working and I thought maybe it's time to take it easy. But this may change my mind.
As for reaction to winning the world's most prestigious literary prize, the woman who has become so beloved for her dazzling use of language had only a few words: "It's just great," she said.
Note to readers: This is a corrected story. Previous versions misspelled the first name of Hermann Hesse.