Moseley's creative partner is due to be announced shortly. Both executive creative directors will take up their posts in January next year and will join Wieden & Kennedy Amsterdam's managing director, David Miller, to head the European agency.
Moseley and his new partner replace the two creative heads, Paul Shearer and Jon Matthews, who left the agency last year. The pair will manage the creative work across all the agency's clients, including Heineken, Sharp, Nike Europe, Vodafone and TNT Express.
Moseley has spent the past two years working at Mother and was involved in both the Boots and Orange pitches. Previously, he worked as a creative director at TBWA\London on PlayStation, Apple, The Labour Party and Strongbow Cider.
Moseley said: "I've loved my time at Mother but this is going to be really special. There are some things in life you just can't say no to. So I said yes. Wieden & Kennedy is the ultimate network. It is as iconic in our business as the brands it advertises."
Miller added: "This is fantastic news for Wieden & Kennedy Amsterdam and for the company globally. We have been thorough and thoughtful in our search for creative leadership, and Al is the right choice. It will be great fun working with him."