Fahy, who has 15 years experience in the marketing industry, will be responsible for overseeing all of Yahoo! Europe's brand development, customer insight and communications strategies across the continent.
He joins the European arm of Yahoo! at a time of substantial change. Earlier this month, the digital giant said it would consider closing down or selling off underperforming parts of its European operations, if they fail to make a substantial improvement by the first quarter of 2008.
The European arm lost its vice-president of media and communications, Jon Gisby, to Channel 4 earlier this month. It is taking a close look at its operations and has emphasised that it needs to start matching the performance of its Asian and US counterparts.
Prior to joining Yahoo! Europe, Fahy was at wireless communication company Research in Motion, where he was brand marketing director for BlackBerry in the Europe, Middle East and Africa regions, and drove customer awareness and sales.
He also held a number of positions at Orange between 1999 and 2005, the most senior of which was director of global brand communications.
He is a former head of brand planning and advertising at Orange UK, where he was responsible for creative direction programmes for the launch of Orange 3G, PrePay Repay and the mobile giant's The Future's Bright On/Off campaign.
Toby Coppel, managing director of Yahoo! Europe, said: "Kristof has world class marketing and communications credentials and has demonstrated he can execute marketing strategies with both a strategic focus and creative flair."