He was born in Kansas City. His father, Eert Ubbe Iwerks, emigrated to the U.S. in 1869 from the village of Uttum in East Frisia (northwest Germany, today part of the municipality of Krummhörn). Ub's birth name can be seen on early “Alice” shorts that he signed. Several years later he simplified his name to “Ub Iwerks”, sometimes written as "U. B. Iwerks". He is the father of Disney Legend Don Iwerks and grandfather to documentary film producer Leslie Iwerks.