David Pegler, currently managing director, becomes chief executive with effect from 1 January and there are no plans to appoint a replacement managing director.
Meanwhile, James Rees, director of conferences and events at the venue, has been promoted to executive director and will also sit on the executive management team from January 2013.
In his new role as chairman, Murphy will concentrate on developing and strengthening Excel London’s partnerships with local and national government to gain greater recognition and support for London as a global centre for business tourism.
A board member of London and Partners, Murphy will continue to work to attract international businesses to meet and exhibit in the UK capital city, so that it can achieve its aims with the Mayor of London, Boris Johnson, to reach number 1 in the ICCA rankings.
Murphy said: "Excel London has had a huge positive impact on the London economy and has helped to attract some of the world’s leading events to our capital city.
"Exhibitions, conferences, meetings and corporate hospitality contributes £30.3 billion to the annual British economy and is the UK’s fifth biggest industry in employment terms, more than financial services, transport and construction and level with education. We therefore need to raise the profile of the importance of our industry and garner support from government so that we can be more competitive in the global marketplace."
In 2012, Excel London welcomed 5m visitors through its doors, played host to seven Olympic events, six Paralympic events and contributed more than £1.8bn in economic impact to London.
Meanwhile, in October 2012, London Mayor, Boris Johnson joined David Pegler and Kevin Murphy to announce that Excel had been selected by the European Society of Cardiology for the world’s largest medical congress in 2015.
The congress will bring 35,000 medical professionals to the capital for the five-day event and is expected to be worth approximately £80m to the London economy.