On Saturday, Buffett, speaking at the 53rd annual general meeting of Berkshire Hathaway, said the Vanguard founder "probably (has) done more for the average investor than" anyone. The Berkshire chairman and CEO called him out to stand for an ovation. The comments came before Bogle's birthday on Monday.
Bogle said he wrote Buffett a letter to thank him, but added he's "an ordinary guy."
"I'm not a hero," Bogle, 88, said on "Squawk on the Street." "I'm just an ordinary guy who has tried to do my best for investors and who gave a damn about the people who were investing and wanted to make sure they got a fair shake. If that's heroism, then so be it."
Bogle, sometimes called the king of index funds, founded Vanguard in 1975. The investment management company later launched the first low-cost index mutual fund. Today it has more than $4 trillion in assets under management.
The Vanguard founder has encouraged investors to own the stock market and diversify, and to buy at a low cost and invest for the long term. (Here are other tips from Bogle.)
On Monday, Bogle said indexing is here to stay, and feels good about getting "the ball rolling" years ago.
"I don't look at the traditional funds as being threatened," Bogle said, when discussing the rise of ETFs. "They're total international, total bond market. Those are the dominate forms of investment for the traditional funds like ours. That's where the money is going mostly."
—CNBC's Trent Gillies contributed to this report.