D avid Duffield is a legendary American software entrepreneur who has founded two of the most successful enterprise software companies in history: PeopleSoft and Workday. An engineer by training, Duffield founded PeopleSoft in 1987, pioneering the development of client-server human resources and finance software. He built the company into a major player in the enterprise software market, known for its strong corporate culture.

After PeopleSoft was acquired by its rival Oracle in a long and hostile takeover battle in 2005, Duffield, then in his 60s, came out of retirement to start again. He co-founded Workday with his trusted lieutenant, Aneel Bhusri, with the goal of building a new generation of human resources and financial management software from the ground up, based entirely in the cloud. Workday has been a massive success, becoming a leader in the cloud-based enterprise software market. Duffield is also a major philanthropist, particularly for animal welfare, through his foundation, Maddie's Fund.