Ko, who was born in South Korea and moved to New Zealand when she was six, was the youngest player to win a professional tournament when she clinched the New South Wales Open in Sydney aged 14.
Her mother Tina had confirmed earlier this month that her daughter had asked the LPGA for an exemption. Ko formally announced her decision to turn pro last week via social media.
The LPGA Tour has an 18-year-old age requirement for membership but commissioner Mike Whan said they have made an exception for Ko.
"After reviewing Lydia Ko's petition, I have granted her LPGA Tour membership beginning at the start of the 2014 season," Whan said in a statement. "We are looking forward to having Lydia as a full-time member for the 2014 season.
"It is not often that the LPGA welcomes a rookie who is already a back-to-back LPGA Tour champion."
The teenager became the youngest winner on the LPGA Tour when she captured last year's Canadian Open at the age of 15.
Ko was also the youngest champion on the European Tour with her triumph in the New Zealand Open last February and then successfully defended her Canadian Open title this year.
"I am very excited to become a member on the LPGA Tour. It has always been my dream goal to play on the LPGA, and play against the world's best players," Ko said.
"I know that becoming a member is not only performing well, but to deal with responsibilities very well.
"Women's golf is growing day by day and I would love to be able to inspire other girls to take up the game, and go for it."
- Sports & Recreation
- Lydia Ko