The Interpublic network won the business after a final pitch against MediaCom.
Creativebrief handled the review process, which had seen OMD exit at an earlier stage. UM's sister agency Initiative was the incumbent on the UK account.
UM will work for Ecco, which produces children's shoes, outdoor and sports footwear, across Europe and in the US and China.
The retailer has recently launched stores in Oxford, Guildford and Manchester, and is thought to be planning a major brand push in the autumn.
The company was founded in 1963 in Bredebro, Denmark and is owned by the Toosbuy family.
Patrick Ryan, the new-business director at Universal McCann, said: "Ecco is a very unique brand that knows exactly what it is and where it wants to go. It has impressive expansion goals globally and UM is hugely excited to be chosen as its global strategic and media partner."
The Ecco win follows UM's capture of the international planning and buying brief for Burberry in April.
The network landed the business after a six-month pitch process that culminated in a head-to-head battle with WPP's Mindshare.