Kenneth Wayne Jennings III holds the record for the longest winning streak on the U.S. syndicated game show Jeopardy! Jennings won 74 games before he was defeated by challenger Nancy Zerg on his 75th appearance. His total earnings on Jeopardy! are US$3,022,700 ($2,520,700 in winnings, a $2,000 consolation prize on his 75th appearance, and $500,000 in the Jeopardy! Ultimate Tournament of Champions). Jennings held the record for most winnings on any game show ever played until the end of the Ultimate Tournament of Champions (first aired on May 25, 2005), when he was displaced by Brad Rutter, who defeated Jennings in that tournament.
After winning, he began working on a book, Brainiac: Adventures in the Curious, Competitive, Compulsive World of Trivia Buffs, which explored American trivia history and culture. Ken also appeared as a member of the mob sitting in podium #13 from the new game show 1 vs. 100 in 2006, and in 2007 Jennings was the champion of the first season of the US version of Grand Slam.
Jennings was selected to co-host Jeopardy after the death of Alex Trebek.