As of today, David Karp is one of the richest, 20-something entrepreneurs in America.
But his dad says the sudden wealth—his 26-year-old son stands to make more than $200 million on the sale of the blogging website to Yahoo, announced on Monday—won't change David's work or outlook on life.
"He's going to keep on doing what he's doing," said Michael Karp, a New York-based composer of TV and film music themes. "It's never about the money with David. It's always been about doing what he loves doing. And creativity and passion."
He added that David is a very "thoughtful and down-to-earth guy" who won't let the money go to his head.
It remains to be seen how Tumblr and Karp will do under Yahoo's ownership. Michael Karp said he was with his son Monday morning at New York-based Tumblr when the announcement came, and David was "thrilled."
(Read More: Yahoo Agrees to Buy Tumblr)
He said David looks forward to continuing to run the company. "He's extremely passionate about what he does and about Tumblr," Michael Karp said. "He's going to focus on building the company. He loves the people he works with."