The News understands that Mr Cooper will be leaving the role on November 18, but the Kings declined, when asked, to give a reason for his departure.
Mr Cooper joined The Kings in October 2006 and during his tenure has been instrumental in developing a number of key projects at the Albert Road, Southsea venue.
Mr Cooper said in statement released by the theatre: ‘My time at the Kings Theatre has been incredibly rewarding and I have had the opportunity to meet and work with some fantastic people on stage, behind the scenes and throughout the city.
‘I am looking forward to taking on new professional challenges and wish the theatre and everyone involved continuing success in what I have no doubt will be an exciting, prosperous future.’
The News approached the Kings, to speak to Mr Cooper but was told he had nothing further to add.
A well-known figure in the community, Mr Cooper has promoted numerous schemes both locally and internationally to bring the theatre to a wider audience.
There have been a number of successful co-productions with House of Burlesque, Icarus Theatre Collective and Teatro Nuovo-Verona in Italy, which included a promenade production of Romeo and Juliet performed in and around Juliet’s famous courtyard in Verona.
Since the launch of the Kings Youth Theatre in 2010, he has overseen its successful growth to more than 100 members, offering unrivalled opportunities for young people to get involved with the arts.
Mr Cooper has also promoted work-based learning and apprenticeships at the venue.
Throughout the past decade he has supported the trust in its restoration of the theatre and recently announced The Big Project, a new multi-million pound programme of restoration and development to build a sustainable future for the Kings.
Around the turn of the century, the Edwardian theatre came under threat of closure.
In 2001 the theatre was bought by Portsmouth City Council and leased to the Kings Theatre Trust Ltd.
Since 2003 it has been managed by the trust as a voluntary charitable trust.
Ron Hasker, chairman of the trustees, said: ‘We would not be where we are today without David’s leadership and we have enjoyed many successes with his guidance.
‘Now, as the theatre moves forward to the next chapter in order to face the new challenges ahead, we wish David all the very best in his new ventures.’