Otto was born in 948, the only son of Conrad the Red, Duke of Lotharingia since 944, and Liutgarde of Saxony, daughter of Emperor Otto I. As a grandson of the Holy Roman Emperor, Otto was born into a life of power. His mother died five years after he was born, at age 21, and Otto lived much of his early life in his grandfather"s court till his death in 973 at age 61, when Otto was 25.
Otto of Worms is first documented as a count in the Nahegau about 956, he also held the Speyergau and Wormsgau, as well as several other counties in the area. He could at least retain the ducal title as "Duke of Worms", received the Kaiserpfalz of Lautern and seized large estates of Wissembourg (Weißenburg) Abbey in compensation. Upon the death of Duke Henry II of Bavaria in 995, Otto at first received the March of Verona back, while Carinthia passed to Henry"s son Duke Henry IV of Bavaria.
When Emperor Otto III had died in 1002, Otto of Worms and Henry IV of Bavaria were candidates for the election as King of the Romans.
Otto withdrew and received the Duchy of Carinthia from the newly elected king Henry (then Henry II of Germany) in return. Nevertheless he was forced to cede his Rhenish possessions to his long-time rival Bishop Burchard of Worms.
Otto married Judith (died 991), probably a granddaughter of Duke Arnulf the Bad of Bavaria. They had the following known children:
Henry of Speyer (died before 1000), Count in the Wormsgau
Brun (died 999), ruled as Pope Gregory V from 996
Conrad I, Duke of Carinthia (1004–1011)
William, Bishop of Strasbourg (1028–1047).
