David Karp (born July 6, 1986)[1] is an American businessperson, best known as the founder and former CEO of the microblogging platform Tumblr.

[2][3] Karp began his career, without receiving a high school diploma, as an intern under Fred Seibert at the animation company Frederator Studios, where he built the studio's first blogging platform and conceived, wrote, and edited their first internet video network, Channel Frederator.

His parents are Barbara Ackerman, a science teacher from San Anselmo, California, and Michael D. Karp, a film and television composer.

[9] Karp attended the Calhoun School from pre-school through eighth grade, where his mother teaches science.

[2] Karp went on to attend The Bronx High School of Science for one year before dropping out in 2001 and started homeschooling.

[9] Karp began as an intern in 2000 for animation producer Fred Seibert, founder of Frederator Studios.

After he started homeschooling, Karp also began taking Japanese classes at the Japan Society and saw a math tutor, with whom he worked on writing software for winning at blackjack and poker.

[11] When entrepreneur John Maloney sought technical help with UrbanBaby, an online parenting forum, a Frederator employee recommended Karp for the job.

After a year of waiting, Karp and Arment began working on their own microblogging platform during a two-week gap between contracts in 2006.