She moves on after nine years working at London & Partners and previously at Visit London. The move comes as part of a post-London 2012 executive team restructure.
Ainsworth-Wells said: ‘I feel I have achieved everything I can for London and I am leaving on a phenomenal high. I hope to provide other cities with the insights and experience I have gained in London.’
She declined to reveal what her next move would be, although she said that she would be making an announcement shortly.
London & Partners was launched last April as a merged quango to handle the work of three London-based agencies - Visit, Think and Study London, which saw Ainsworth-Wells' team grow to 24 people.
During the London Olympics, Ainsworth-Wells oversaw the London Media Centre, which catered for the 8,164 non-accredited media that were in the capital.
Before working at Visit London, Ainsworth-Wells was client services director at USP Group and promotions manager at the London Evening Standard.
At the time of going to press London & Partners was yet to confirm who would assume Ainsworth-Wells’ responsibilities or whether a direct replacement would be sought.