Published Thursday, 07 May 2009
Mr Gilligan succeeds Sir Desmond Rea, having served as his deputy since 2006, while independent board member Brian Rea will now become the vice-chairman.
The board is made up of politicians drawn from the main parties, and independents, who together oversee policing.
The search is also set to begin to identify candidates to replace Sir Hugh Orde, who later this year will leave Northern Ireland to head up the Association of Chief Police Officers.
Mr Gilligan, who runs his own property, investment and development company, will take-up his post on June 1.
"I am honoured to be elected by my board colleagues to take on the role of chair and look forward to leading the board over the next two years," he said.
"The Policing Board has come a long way since its inception in 2001 and through its oversight role, has played a major part in the delivery of the policing reform process.
"With the process now in place to facilitate the devolution of policing and justice, policing and the work of the board remains a matter of public and political interest."
"At this time we are dealing with some key issues, not least the appointment of a new chief constable and deputy chief constable."
Mr Gilligan also paid tribute to outgoing chairman Sir Desmond.
"Policing in Northern Ireland has played a central role in moving the peace process forward and Sir Desmond has played a key part in that as chairman of the board," he said.
Despite stepping down as chairman, Sir Desmond will remain an independent member of the board for a further two years.