Ulric was created Count of Weimar when still a child in 1067. He inherited both of his father's marches on the death of his brother Poppo II in 1098, but was divested of Istria sometime between 1101 and 1107, when it went to Engelbert II of Sponheim, whose father had preceded Ulric's brother in the march. Ulric was described as de Saxonie principus. He married Adelaide (died 1146), daughter of Louis II, Count of Thuringia, but left no children. His sister Adelaide passed on the Carniolan inheritance to her grandson Conrad I, Duke of Merania.