Dai is one of the few female co-founders of American semiconductor companies, and since it began in 1995, she directed Marvell’s rise to become one of the top semiconductor companies in the world. During her time at Marvell, Dai worked on strategic partnerships and Marvell's Technology is used in products in several markets. Dai has also become a driving force in expanding access to Technology in the developing world and an ambassador of opportunity between the US and China. Dai advocates for getting more women involved in science and Technology.

In 2008, the company and its then chief operating officer–and the only member of its stock option “committee” during the period in question – Weili Dai paid fines, to the Securities and Exchange Commission over charges of false financial information to Investors by improperly backdating stock option grants to employees, totaling $10 million and $500,000 respectively. Dai was forced to step down as executive vice President, chief operating officer, and a Director but allowed continue with the company in a non-management position.

Newsweek named Dai one of the "150 Women Who Shake the World". She was profiled by CNN International for the Leading Women Innovator Series. In 2004, Dai was an Award Recipient for the Northern California Region of the EY Entrepreneur of the Year award. On May 12, 2012, Dai became the first female commencement speaker in the UC Berkeley College of Engineering's 143-year history. On August 22, 2012, Dai was on the Forbes list of “The World’s 100 Most Powerful Women.” In October 2012, she was awarded the Outstanding Leadership Award by the non-profit organization Upwardly Global. In March 2013, Dai was honored with the Silicon Valley Entrepreneur of the Year Award in the Established Corporation category by the Chinese Institute of Engineers/USA-San Francisco Bay Area Chapter (CIE/USA-SF). On May 23, 2013, Dai was No. 88 on the Forbes list of "The World's Most Powerful Women." On June 12, 2013, Dai was named a 2013 Most Influential Women in Embedded. On Oct. 25, 2013, Dai was honored with the New Silk Road Award by the California-Asia Business Council. On Nov. 13, 2013, Dai was awarded the Gold Stevie Award for Woman of the Year – Technology. On Dec. 16, 2013, Marvell Co-founders Dr. Sehat Sutardja and Weili Dai were honored with the 2013 Dr. Morris Chang Exemplary Leadership Award by the Global Semiconductor Alliance. On May 28, 2014, Ms. Dai was named to Forbes Most Powerful Women list. On Sept. 8, 2014, Dai, was honored with a Gold award as the “Best Woman Professional of the Year” at the 2014 Golden Bridge Awards. On Nov. 17, 2014, Ms. Dai was honored with the Gold Stevie® Award for Female Entrepreneur of the Year – Business Products. On Dec. 9, 2014, Ms. Dai was honored as a Gold Winner for 2014 Women World Awards. On May 26, 2015 Weili Dai was named as the 95th most powerful woman in the world by Forbes, her fourth consecutive year on Forbes list of "The World's Most Powerful Women." On Aug. 5, 2015, Ms. Dai received a Gold recognition for "Technology Executive of the Year" from the 2015 International Best in Biz Awards. On Oct. 14, 2015, Ms. Dai was named a recipient of the "Keepers of the American Dream" by The National Immigration Forum and National Immigration Forum Action Fund.

Dai promoted partnership with the One Laptop Per Child program (OLPC). Ms. Dai also is active in STEM stating, "Women are the Future of Technology and today's Technology is fun and cool. It's not just about developing ‘nerdy’ stuff it's about turning Technology into fashionable and user-friendly smart solutions. A woman's natural talent is design, and the look and feel, and making these things fit into our lifestyles. I believe by embracing STEM and leveraging inherent strength of women—the sense of responsibility, passion, compassion, and pride we dedicate to family and community—and applying it to Business can make women the X factor in the new era of global growth and prosperity for the ‘Smart Life and Smart Lifestyle.'" She sits on the board of the disaster relief organization, Give2Asia, and was named to the Committee of 100, an organization representing the Chinese Americans. Sutardja Dai Hall at her alma mater UC Berkeley was named for Dai along with her husband Sehat Sutardja, CEO of Marvell and Pantas Sutardja, CTO of Marvell. Sutardja Dai Hall is home to the Center for Information Technology Research in the Interest of Society (CITRIS). In 2015, Ms. Dai was named to the Global Semiconductor Alliance's (GSA) Board of Directors, helping to foster and accelerate the growth of the silicon industry across the globe. Ms. Dai also is a member of the executive committee for TechNet.