"By including writers from around the world to compete alongside Commonwealth and Irish writers, the Man Booker Prize is reinforcing its standing as the most important literary award in the English-speaking world."
The change will come into effect for the 2014 award.
Previous winners of the Booker, one of the world's richest literary prizes, include English novelist Hilary Mantel, Australian author Peter Carey and the South African J.M. Coetzee.
The Booker has long held out from recognising American authors, fearing that the powerful US literary scene, backed by wealthy academia and creative writing programmes, would swamp the output from the rest of the world.
Taylor said the prize's trustees "have not made this decision quickly or lightly" and it followed 18 months of consultation with the publishing world.
"Initially the thinking was that we might set up a new prize specifically for US writers. But at the end of the process we were wary of jeopardising or diluting the existing Man Booker Prize," he said.
"Instead we agreed that the prize, which for 45 years has been the touchstone for literary fiction written in English of the highest quality, could enhance its prestige and reputation through expansion, rather than by setting up a separate prize."
Novels must still have been published in Britain and entered by their British publisher, he said.
The literary world was divided by the announcement.
Irish novelist John Banville, who won the Booker in 2005 for his novel "The Sea", welcomed the greater inclusiveness but said it would make life "very difficult for the judges."
"They will have to limit how many books can enter, somehow," he told the BBC.
The prize is awarded to a specific book, rather than an author, and is evaluated by a group of judges who compile a long list of novels, followed by a shortlist and then select the final winner.
British writer and broadcaster Melvyn Bragg however said the Booker "will now lose its distinctiveness. It's rather like a British company being taken over by some worldwide conglomerate."
But Taylor said the newly expanded prize was "embracing the freedom of English in all its vigour, its vitality, its versatility and its glory wherever it may be.
"We are abandoning the constraints of geography and national boundaries."
The results of this year's edition are due on October 15, with the candidates including Zimbabwean novelist NoViolet Bulawayo, the first black African woman to make the Booker shortlist.
The Booker's expansion comes ahead of the start in March of a rival award -- the Folio Prize -- which also honours English language fiction published in the UK. It has a £40,000 prize.
The Man Booker foundation also awards a separate, yearly Man Booker International Prize which recognises a writer's overall contribution to world fiction that has been either written in or translated into English.
Winners of the international award include the American novelist Philip Roth, in 2011.
Until 2012 Man also sponsored the Man Asian Literary Prize.
The Booker got its name from its initial sponsor in 1968, the food wholesale company Booker-McConnell. The investment company Man Group took over sponsorship in 2002 but kept the name.