Jose Maria Olazabal's team retained the famous trophy with a thrilling comeback in the singles event at Medinah.
Trailing 10-6 overnight, Europe won the first five matches on Sunday before eventually prevailing as 14 1/2-13 1/2 victors.
"This feels unbelievable," McIlroy told BBC Sport. "We knew that America did that to us in 1999 in Brookline. We had to get blue on the board early and the first five guys did that.
"I played the best I've played all week today. We've done it for Seve. Jose has been so inspirational in the team room and so emotional. It's so good we got to do this for him."
Ballesteros died in May last year after a long battle with cancer. He captained Europe to victory in his native Spain in 1997.