The new position has been created after a restructure in the company's sales force.
As sales director Lawrence-Jones, who has worked across Haymarket titles including Management Today, Campaign and Revolution, will be responsible for the development of relationships with agencies and specialists.
One of his first tasks will be to recruit a sales manager and a sales executive to work across the poster specialists and their agencies.
Richard Camillieri, In Situ Media's managing director, said: "We're delighted to bring someone of Dominic's calibre into the out-of-home industry. He'll bring extensive advertising experience to the role and a passion for quality and service excellence."
Lawrence-Jones said: "The leisure centre media business is entering an exciting period with, among other things, the world's greatest sporting spectacle just around the corner boosting interest in a wide range of sporting activities."
In Situ recently announced plans to spend £250,000 on upgrading its portfolio of panels inside more than 600 leisure centres in the UK.