Atwell chose to dedicate the award - US$1m worth - to the Centre for Teaching and Learning (CTL), the non-profit demonstration school she founded 25 years ago, which she said is in need of upgrades, including a new roof and furnaces, and many more books. "We will have a very healthy book-buying fund," Atwell said. "It's the thing we never have enough of."

Atwell's prolific teaching career spans four decades and several school districts. She is also the author of nine books for teachers, including , which sold half a million copies. Her goal, she said, is to make the classroom a place for "wisdom and happiness", rather than one of stress and frustration.

The world's top educator, however, said she never intended to become a teacher. Instead, she fell into the position while trying to figure out what to do with an English degree. After graduation, she took a student teaching position as a "fallback plan".

"I fell in love with teaching," she said. "I felt like I was home. I love literature and I really loved adolescents, I found out. And to have relationships with kids around books and to talk to kids about books seemed like the best gig in the world."

She began teaching in New York in 1973, starting out with a classroom full of children aged between 12 and 14 in the seventh and eighth grades, her favourite grades. "When you hook seventh and eighth graders on something, I think you've hooked them for life," Atwell said. "It's such an important age in terms of kids establishing their world view and figuring out how the adult world works."

But during these early years, Atwell realised children weren't "hooked" on the books or writing prompts she assigned. She began researching alternative teaching methods and stumbled on the work of Donald Graves, a University of New Hampshire professor of early childhood education who is credited with pioneering the "Writing Workshop" teaching method that Atwell dedicated her career to improving.

Writing Workshop is a teaching framework that champions choice and self-expression. Children choose their own books and writing topics, advance at their own pace and spend one-on-one time with teachers. This discovery revolutionised her classroom. She immediately noticed pupil engagement increased when the children were allowed to choose what they wanted to read and write. "When I let go of my last bit of total control of everything in the classroom and let [the children] choose, they made wonderful choices - smart choices."

While still working in the confines of the state school system, Atwell had no choice but to innovate without permission. "I closed the door of my classroom and talked to my kids," she said. "I've found, consistently, kids know what's interesting and what's valuable if we let them have some say in it."

After teaching in New York, Atwell moved to Maine, where in 1990 she founded CTL to experiment and share new ideas of teaching writing and reading. The school serves a maximum of 80 pupils from kindergarten to eighth grade.

At the school, teachers engage with students as fellow writers and readers, rather than the traditional instructor-pupil relationship. Each day the children spend time reading books they have chosen. They even curate a website of recommended books for other young readers. And Atwell makes a point of exposing them to as many cultures and traditions as possible.

"We celebrate the Chinese New Year, the Day of the Dead, the start of Lent, the end of Ramadan," she said. "I want them to have a knowledge of and passion for the whole of society, and not just the tiny little slice they're exposed to here in rural Maine."

Every year teachers from across the country visit the school to observe the Writing Workshop method in action - and, Atwell hopes, integrate it into their own classrooms. The method has proven to work in diverse classrooms of children from all different cultures and socio-economic backgrounds, she said.

The majority of her pupils excel in high school, and 97 per cent go on to study at college or university. But when she looks at the nation's vast state school system, with its rigid infrastructure and focus on standardised testing, Atwell said she sees a wholly detrimental shift toward uniformity in the classroom.

"Teachers are being essentially asked to be technicians, to read a script, and the script is not valid," Atwell said. "[Test scores] are all that counts right now. It's all data analysis, metrics and accountability. It's a business model that has no business being applied to the craft of teaching or the science of learning."

Atwell disagrees with the politically-contentious common core educational standards, which she believes focuses too much on test scores, rather than lessons learned, or books read, as a mark of achievement. Students all learn at different paces and levels, and the common core standards steamrolls individuality and forces everyone to be quite literally on the same page, she said.

On receiving the award, Atwell said she was "gobsmacked". She said the attention-grabbing prize is affirmation that the non-traditional teaching methods she has championed for more than four decades are not only valued and prized but are, more importantly, successful.

"I think the one thing we had in common, and it was really powerful to see this, was that none of us talked about test scores," Atwell said. "We were talking about making meaningful changes in kids' lives. I am so proud to be a part of a group of people who are professionals in every sense of the word. You just feel proud to be a teacher who was chosen to represent the profession."

So what's next for the world's greatest teacher? Back to school, of course.

Competition highlights privilege of teaching

The US$1 million award for teaching is made by the Dubai-based Varkey Foundation. It recognises outstanding contributions to the profession.

US teacher Nancie Atwell fought off competition from 10 global finalists to become the first recipient of the Global Teacher Prize. The other nine finalists were from countries including Afghanistan, India, and Cambodia. The 10 finalists were themselves whittled down from of thousands of nominations.

The winner was announced at a ceremony in Dubai earlier this month. The event was attended by former US president Bill Clinton, Paul Kagame, the president of Rwanda, and Sheikh Mohammed bin Rashid al- Maktoum, Prime Minister of the United Arab Emirates and leader of Dubai.

Speaking at the ceremony, Clinton said: "I think the most important thing this prize has done has re-awaken the world's appreciation of the importance of teachers."

Atwell said she was honoured to accept the award. "I hope to convey to young people considering teaching that it's a privilege," she said.

Richard Spencer, a British science teacher from Middlesbrough College, Teesside, in northern England, who was among the final 10, said he enjoyed every minute of the experience. "The one thing we all have in common is enthusiasm for what we do," he said.

Spencer said teaching was not viewed with prestige in the UK. "[But] there's nothing greater than moulding the next generation and helping young people succeed," he said.

Vikas Pota, the chief executive of the Varkey Foundation, hoped the prize would elevate the status of teachers around the world.

Atwell hoped the award would send a positive message about the profession. "I hope this will invite creative, smart young people to consider teaching as a career, because now it's become more difficult in the US to attract smart young people to teaching. They see it more as an act of being a technician who administers a programme, not a reflective practitioner."