Jennings, 30, has broken records for not only "Jeopardy," but also for overall game show winnings since he began his run June 2, defeating 150 challengers.
Ventura, Calif., Realtor Nancy Zerg bested Jennings in his 75th appearance.
Zerg, a former actress who bypassed college for a life of theatre, music and travel, went into the final round trailing Jennings by $4,400. The third contestant did not make the final round.
Under the category, business and industry, the final "Jeopardy" answer was: "Most of this firm's 70,000 seasonal white-collar employees work only four months a year.
Zerg supplied the correct question: "What is H&R Block?" to bring her winnings to $14,401. Jennings incorrectly wrote, "What is Fed Ex?" and dropped to second place with $8,799.
The players received a standing ovation.
"It hasn't sunk in," Zerg said. "I think we both played well, but I got lucky with categories that I knew and he just happened to hit a couple of Daily Double clues that he didn't know."
During his run, he gave more than 2,700 correct responses on subjects from Shakespeare to hip-hop.
"During my life, I think I made a lot of safe and practical choices," Jennings said. "I never took a chance or did something that for me would be a dream. And being on 'Jeopardy' has been that dream."
Jennings said he has hung on to his job through his "Jeopardy" appearances. But, he added, "I might work fewer hours from now on."
A "Jeopardy" rule change last season allows contestants to continue playing as long as they keep winning. Previously, contestants were limited to five consecutive appearances.