Otto I continued his grandfather's policy of expansion to the west against the Duchy of Westphalia which was owned by the Archbishops of Cologne.
Count Otto I's efforts led to significant success in expanding the territory controlled by Waldeck.
In 1305, a feud broke out in Eichsfeld, where Otto's enemies, the Lords of Strive and Adelebsen, were opposing the city of Heiligenstadt.
During this feud, Otto was captured by his enemies, put in a dungeon and strangled against the rules of martial law.
[2] Otto I married prior to 14 November 1276 to Sophia (c.1264 – 1340), daughter of Henry I, Landgrave of Hesse.