The German held his nerve to make a five-foot par putt on the final hole of his singles match with Steve Stricker to ensure that Europe retained the trophy they won in Wales two years ago.
He raised his arms high, pumped his fists and then ran into the fairway and jumped into the arms of Europe captain Jose Maria Olazabal.
"It's a feeling I never had before," said Kaymer, a former world number one and Major winner, who later gave special thanks to compatriot Bernhard Langer.
Kaymer had been out of form before his final day win over Stricker and had sought some advice from Langer, who missed a deciding six-foot putt at the Ryder Cup 21 years ago at Kiawah Island.
"On Friday I sat down with Bernhard and talked to him a little bit about the Ryder Cup because my attitude wasn't the right one," Kaymer said.
Kaymer lost the only match he played on Friday's opening day and was passed over by Olazabal when he decided the line-ups for Saturday's matches.
The German said he felt hurt about being dropped but was determined to show his captain he could play.
"To be honest it was very difficult yesterday. You want to prove that you can do better than what I showed on Friday, because on Friday I didn't show good golf.
"And then I took the possibility to talk to Bernhard a little bit yesterday," said Kaymer.
"I asked him if we could sit down on Saturday morning and talk about the Ryder Cup, because I felt like my attitude...was not as inspired as I should be."
On Sunday, all 12 players on both teams compete in singles, and the German stepped up to the challenge. He said he thought about Langer when he faced the critical putt at 18th.
Had Kaymer missed it, Tiger Woods would have had the chance to win the Cup for the US in his match with Italy's Francesco Molinari, who he led one up after 17 holes in the final match.
"I did think about him, especially when I walked around the hole and read the putt from the other side. And to be honest, there was a footprint in my line, but it was not that bad," said Kaymer, referring to a spike mark that hampered Langer in 1991.
"So I thought, OK, it's not going to happen again, it's not going to happen again. And to be honest with you, I didn't really think about missing. There was only one choice you have. You have to make it.
"When it went in, I was just very happy, and that is something that I will remember probably for the rest of my life and hopefully I can talk about when I have some grandchildren one day."
Kaymer won the 2010 US PGA Championship in dramatic style, beating Bubba Watson in a three-hole playoff but said winning the Ryder Cup was more special.
"The Major was just for myself, but I can see the guys behind me, my brother was here and my father was here," Kaymer said.
"Sergio (Garcia) ran onto the green. It's so much more behind me. Now I know how it really feels to win the Ryder Cup."
- Bernhard Langer