Asked by the Otago Daily Times if she thought residents would be surprised by her move after two and a-half years in the job, Ms Lawson said it was no surprise as her contract expired in September.
"I took the time to think about my long-term career path and it was a tough decision, but I really want to move on in the area that I have experience in the UK, which is public-private partnership.
"So that's it, I'm very relaxed about the decision. It's entirely my own decision, but purely based upon me. At my age, it's important you make really good long-term decisions and are right for you at the time."
Asked if she thought her chief executive's office had been quiet, compared with predecessor Duncan Field's high profile over 12 years, Ms Lawson said a chief executive had to work out a relationship with the mayor.
"It doesn't always work to have a chief executive and a mayor that's out there. My job is to support the mayor and the council and I've been very happy to do that."
Asked to describe her relationship with Queenstown Lakes Mayor Vanessa van Uden, Ms Lawson said it was "really constructive".
"We care a lot about the same things, but we're different people and we'll get there in different ways."
Ms Lawson declined to say if there were disagreements between them.
"I've really enjoyed my two years here. I've learned a lot, the people have been great and I've been really happy to be part of this amazing community.
"I'm proud of what I've achieved in two years, so I've got no regrets really and I felt it was right to give council proper notice so they can plan my replacement.
"Also, there has been a bit of chatter around town and out of respect for the team here, I wanted to be clear and to let them know."
Ms Lawson said she was proud of the work done in the Shaping our Future forums, which informed the council's events strategy, as well the work towards greater council transparency.
Ms van Uden, in a statement yesterday, acknowledged Ms Lawson's "commitment to strengthen the long-term financial position of the council with a focus on value for money and greater accountability".
"On behalf of the council I wish to thank Debra for her service to elected members, the organisation and our community and we wish her well for the future," the mayor said.
"Chief executive" was the final agenda item in the public excluded section, for the full council meeting in Queenstown on Tuesday. A recruitment process will be considered afterwards.
Ms Lawson said she had no immediate plans other than to enjoy the winter season in Queenstown.
