WELLINGTON, October 23, 2013 (AFP) - The 16-year-old has fielded speculation about when she will renounce her amateur status since becoming the youngest ever winner of a professional golf tour event in 2012, when she claimed the New South Wales Open in Australia at the age of 14.
Ko is already fourth in the LPGA rankings and has won four professional events, although she was unable to collect more than US$2 million in prize money and millions more in endorsements because she is an amateur.
She needed a special dispensation from the LPGA to turn professional, as it usually restricts membership to golfers aged 18 and over.
The Korean-born sensation announced her decision on social media, tweeting: "Made a monumental decision today", along with a link to a video of her playing golf with All Black rugby star Israel Dagg.
"I'll do it -- turn pro," she said in the video, adding: "I'm hoping to play a tournament in Florida in mid-November as a professional."
Ko's coach Guy Wilson also used Twitter to confirm the news.
"ITS OFFICIAL!!! @Lko424 is a #PRO. A long time coming but definitely the right time. #LETSGOKO! So SOOO Proud," he tweeted.
New Zealand Golf chief executive Dean Murphy said Ko had topped the world amateur rankings for more than two years, a feat no 16-year-old was ever likely to repeat.
"She has been phenomenal," he said. "Her amateur record ranks right up there among the greats of the game."
Ko was born in South Korea and moved to New Zealand with her parents when she was six.
Pundits such as Tiger Woods' former caddy Steve Williams have long called for her to turn professional and reap the rewards of her prodigious talent.
But Ko and her management team, including her parents, resisted pressure, keeping her enrolled in an Auckland high school and allowing her to concentrate on her exhaustive practise regime, which involves about 50 hours of training a week.
The level-headed adolescent also told AFP last year that she was mindful of the difficulties faced by American Michelle Wie, who has under-performed since turning pro aged 15 in 2005 amid much hype.