The heavy promotion of its 'Make Every Moment Matter' campaign helped William Hill to register record FIFA World Cup-related turnover which resulted in an80% increase compared with the 2010 tournament.
Fahy said on Twitter: "Leaving William Hill in March. What a brilliant five years. Great to have been part of the team that put us back at No.1."
William Hill is also the title sponsor of the PDC World Darts Championship, currently taking place at the Alexandra Palace inLondon. William Hill signed an initial two-year deal with the tournament in April .