Ko sacked Hamilton in mid-October. He had been her for 10 of her 14 LPGA victories, including both her majors.
Leadbetter said his final advice to the 19-year-old Ko was to become more independent, and chart her own destiny.
"My parting words to her were 'Lydia, take control of your own life, take control of your own golf game'," said Leadbetter. "Own your game. You are the player - you need to make these decisions."
The 64-year-old Leadbetter, who has previously coached major champions Nick Faldo, Nick Price and Ernie Els, implied the influence from Ko's parents was becoming overbearing.
"My advice to [her] next coach is it has to be a coach one on one, you can't have the parents involved otherwise it is not going to work," said Leadbetter.
"We have had a pretty good relationship but it is not easy coaching three people at once."
Leadbetter also confirmed that he was intending to continue with Ko into 2017, and the decision to part ways was a unilateral one, coming from the golfer and her management team.
"It was a surprise," said Leadbetter. "You never like to separate from a player but we have had a great three years. Now she and her team - shall we say - have decided they want a change. We only wish them the best.
"Whoever does end up coaching her has got a great young player to help to get to another level."
Leadbetter said Ko was "absolutely spent" after the Olympic campaign in Rio, where she claimed a silver medal, and has been unable to recapture her best form since then.
"She looked burnt out the last part of the year, since the Olympics, and so she didn't play her best golf," said Leadbetter. "She has had a lot more commitments on her time and she has hardly been in the gym the last few weeks. She is only 19 years old and she has a long career ahead of her, if she is managed correctly. She has to manage her game, manage her time, manage her fitness levels."
Leadbetter linked up with Ko in December 2013, soon after her decision to play fulltime on the LPGA tour. It meant an end to her long association with Guy Wilson, who had developed her game over a decade since she was a six-year-old playing at the Pupuke club on the North Shore.
Ko achieved great success with Leadbetter in the first two and a half years of the partnership, but her game has tailed off drastically in the last three months, relative her remarkable standards. Since her last LPGA tournament win in July, Ko has managed only one top five finish in nine tournaments. In four of those events Ko has finished outside the top 40 place-getters.
While Leadbetter yesterday took a lot of the credit for her brilliant performances over most of the last three years, he has also been heavily criticised by sections of the golf media, especially over the ill fated decision to change her swing. And most of the results that were achieved under his tutelage were hardly a surprise, given her incredible success with Wilson as a teenager.
