[13][10][12] After graduating from law school in 1993, Lefkofsky and a college friend, Brad Keywell, borrowed money from relatives to buy Brandon Apparel, a clothing company in Madison, Wisconsin.

[14] In the fall of 2001, Lefkofsky co-founded InnerWorkings, a firm providing print procurement services for mid-sized companies.

[18] In 2012, a merger between MediaBank and Donovan Data Systems created Mediaocean in a deal estimated at $1.5 billion.

[19] In January 2007, Lefkofsky provided $1 million in funding for ThePoint.com, a collective action website started by ex-InnerWorkings employee Andrew Mason.

[21] In April 2010, Digital Sky Technology and Battery Ventures invested $135 million in Groupon at a valuation of $1.35 billion.

[27][28] In 2016, Lefkofsky founded Tempus AI,[29] a technology company that enables physicians to deliver personalized cancer care, and is its CEO.

Its purpose is to advance high-impact initiatives that enhance the quality of human life in the communities they serve.

Lefkofsky taught applied technology at DePaul University's Kellstadt Graduate School of Business.

[35] In November 2007, Easton Studio Press published Lefkofsky's Accelerated Disruption, a book about how technology affects business.