The agency will work on a worldwide campaign to push the relaunch of the single malt whisky.
The firm has been reportedly looking to reposition Glenfiddich to push the quality and uniqueness of the drink.
It has also been looking to attract younger drinkers with the launch of its first global CRM programme earlier this year.
The Glenfiddich Explorers website was created by Kitcatt Nohr Alexander Shaw and aimed to drive greater interactivity among “smart, modern and experienced” 30-something men.
Kitcatt Nohr Alexander Shaw is unaffected by the appointment.
William Grant & Sons appointed Maurice Doyle as its new group marketing director in May. Doyle joined from Bacardi Global Travel Retail and replaces Stephen Sturgeon.
The whisky has eight variants: 12, 15,18, 21, 30, 40 and 50 year-old single malts as well as a 12-year old “Caoran”.
Glenfiddich is distributed in the UK by First Drinks.
William Grant & Sons and Leagas Delaney could not be contacted at the time of publication.