Playing at Defense, Seidenberg was a sixth-round pick in 2001, and he would debut the following season with the Philadelphia Flyers. Seidenberg preferred to stay at his end of the ice, though he was more than capable of the offensive rush when needed. He would have three 30 Point seasons, one with Carolina, one that was shared with Carolina and Florida, and one with the Bruins. That year, he would help Boston win the Stanley Cup. He would also play for Phoenix and the New York Islanders and was in the NHL for 15 seasons.
On the International stage, Seidenberg represented Germany on multiple occasions, and was part of Team Europe, which would surprisingly finish second in the 2016 World Cup of Hockey.