Sacks was born in Cape Town, South Africa, and moved to Tennessee with his family at age five. He attended Memphis University School, earned a bachelor's degree in economics from Stanford University in 1994 and a Juris Doctor from the University of Chicago Law School in 1998. After Stanford he co-wrote The Diversity Myth with Peter Thiel in 1995.
In 1999 Sacks left McKinsey & Company to join Confinity, the startup of Max Levchin, Peter Thiel and Luke Nosek, and became the first product leader of PayPal. As chief operating officer he ran product, sales, business development, fraud operations and other functions through PayPal's February 2002 IPO and eBay's $1.5 billion purchase in October 2002. He then produced and financed the film Thank You for Smoking.
Sacks founded the genealogy site Geni.com in 2006. In 2008 he and Adam Pisoni spun an internal Geni chat tool off as Yammer, an enterprise social network that Microsoft bought for $1.2 billion in July 2012. In January 2016 Zenefits' board made him interim chief executive amid regulatory trouble; he stayed ten months. In late 2017 he co-founded Craft Ventures, which had $3.3 billion under management by 2023 and moved from early to later-stage investing in 2025.
President Trump named Sacks White House AI and crypto czar on December 5, 2024, as a special government employee, and he also chaired the President's Council of Advisors on Science and Technology. He ended his czar tenure in March 2026 but stayed on as co-chair of the council. Since then he has called calls for an AI slowdown a bid for "regulatory capture," and in September 2026 said Anthropic's IPO "must be paused" pending an investigation of a departed researcher's claims.