Paddy Power has appointed the former chief executive of Ulster Bank, Cormac McCarthy, as the company's new chief financial officer.
He will also become an executive director of the company.
Mr McCarthy replaces Jack Massey, who has been named as the company's director of finance and company secretary.
He will resign as an executive director when he takes on his new role in October.
Paddy Power also said that David Johnston, currently the company's secretary and general counsel, will now focus solely on leading an enlarged legal and compliance function as group general counsel.
The bookmakers said it was making the changes to enhance its financial, legal and complaint functions as the company continues to expand. All of the new appointments will take effect from October of this year.
Cormac McCarthy was chief executive of Ulster Bank from 2004 to 2011. He was also a member of the Royal Bank of Scotland group management committee. He jointed Paddy Power as a non-executive director in 2011.
''We have a strong track record of investing for growth and today's appointments represent another step in this direction,'' commented Paddy Power's chief executive Patrick Kennedy.
''The broaden and deepen our capability and capacity in the key areas of finance, legal and compliance and follow our philisophy of hiring, rotating and retaining great talent,'' he added.
Paddy Power said last week revenue for the year to date had risen 28% and it had began to speed up expansion throughout the business following its launch into the Italian online market this week. The company has entered betting markets in Australia, Canada and France, and acquired a games developer in Bulgaria.
It also has a team in San Francisco keeping a close eye on the legality of online gambling in the US.