Moran, who brings 17 years of industry experience to his new role, will be responsible for strengthening the M&C Saatchi-owned agency's creative product across clients including Mini, British Airways, COI and NatWest.
Moran joined Andrews Aldridge shortly after it launched in 1998. He was promoted to the position of creative director in 2004, and has worked on clients including Vodafone, Lloyds TSB, The Arts Fund and RAC.
Thomas said: "Shaun brings experience of heading an award-winning creative department for the past seven years. He has a skill in nurturing and developing creative talent in others. This will be a fresh start for us as an agency."