The midfielder joins on a free transfer and signed a two-year deal through to 2018 with the Wildparkstadion outfit.
An impressive signing
The 29-year-old arrives with plenty of experience and the desire to put a poor season with Paderborn behind him.
Despite two consecutive relegations, he does hold a rather impressive record; his goal against former club, Hannover 96 was the longest in Bundesliga history.
Stoppelkamp has featured over 210 times in Germany's top two divisions, and has enjoyed particular success in the second tier.
27 goals and 26 assists in 142 games, as well as consistent performances, should have Karlsruhe fans excited about their latest arrival.
More good business by Todt
Stopplekamp is not the first player KSC have signed this summer, as they look to build a strong squad for incoming boss, Tomas Oral.
Dimitrios Diamantakos will also join permanently after a successful loan spell from Olympiakos, where he scored eight goals in 24 2. Bundesliga games.
However, there are some notable out-goings. Manuel Gulde, Daniel Gordon, Jonas Meffert and Dominic Pietz - amongst others - are all with new clubs.
Stoppelkamp and Todt have their say
"Moritz is an experienced and prolific attacking all-rounder who can strengthen us immediately. We are excited about it," said Jens Todt, KSC sporting director.
"We had very good discussions that have absolutely convinced me [to join Karlsruhe]," added Stoppelkamp. He was also speaking to the club website.
He concluded, "I want to do my part to go along the path forward here and look forward to the start [of his time with Karlsruhe]."
Quotes via Karlsruher SC.