He was a ruling count of Salm and from 1125 to 1137, he was co-ruler of the County Palatine of the Rhine with his stepson William.
His parents were the German anti-king Hermann of Salm and his wife Sophia of Formbach.
Gertrude was also the sister of Richenza of Northeim, the consort of Emperor Lothair III.
However, King Conrad III of Germany, who had been elected in 1138, decided that the County Palatine was a completed fief, and hence fell back to the King, who gave it to his brother-in-law and devoted supporter Hermann von Stahleck.
Otto married Gertrude, daughter of Henry, Margrave of Frisia.