Waitt was born and raised in Sioux City, Iowa and attended the University of Colorado and left without earning a degree. Waitt and Mike Hammond started Gateway 2000 on September 5, 1985 with a $10,000 loan secured by Waitt's grandmother. The Company began on Waitt's father's cattle ranch in Sioux City, Iowa, moved to Sergeant Bluff, Iowa and later to North Sioux City, South Dakota, where they continued to develop their "down-home" branding, complete with computer boxes printed in a black and white Holstein cow pattern.
Waitt led a move of the company's headquarters from South Dakota to Poway, California in 1998. Waitt relinquished his post as CEO of Gateway in late 1999 to Jeffrey Weitzen, but returned to the post in January 2001.
In 2004, after the acquisition of eMachines, Waitt turned over day-to-day operations of Gateway and the title of CEO to Wayne Inouye, the former CEO of eMachines. In May 2005, he resigned as chairman of the company, ending a near 20-year run with the company he co-founded.
Waitt has been featured on numerous lists by Forbes magazine. He has held a spot on both the Forbes 400 Richest in America as well as Forbes list of the World's Billionaires. He has also been listed on Fortune Magazines "40 Richest Under 40", a list of the 40 wealthiest self-made Americans under the age of 40 in the United States. The 2008 Forbes 400 List listed Waitt with a net worth estimated at $1.4 billion. Waitt fell off the Forbes 400 list in 2009 with a net worth estimate of $900 million. Forbes speculated that the drop from the previous year was as a result of "souring real estate" and a divorce settlement.
According to the September 2002 issue of Fortune Magazine, Waitt sold $1.1 billion in Gateway stock during the dot-com era. In August 2007, Gateway was acquired by Acer Inc. for $1.90 per share or $710 million.
Labeled a maverick by national business and technology publications, he has gone on to form four enterprises that are his chief interests: Avalon Capital Group, Inc., a wholly owned, billion-dollar private investment company with diverse interests in technology, health care, energy, finance, and real estate; and the Waitt Foundation, Waitt Institute and Waitt Institute for Violence Prevention, nonprofit organizations dedicated to the improvement of mankind’s knowledge through historical and scientific exploration.
On November 28, 2016, he was named as chairman of the Salk Institute for Biological Studies Board of Trustees. He originally joined the Salk Board of Trustees in 2004 and has served in numerous roles since as well as making millions of dollars in donations to the Institute.
Waitt owns homes in the Bird Streets area of Hollywood Hills West, Los Angeles (put up for sale for $20 million in September 2015) and in La Jolla, California (purchased in 2005 for $13.32 million and put for sale for $22.9 million in November 2015). Waitt also owns a home in Beverly Hills, California.
Waitt received an honorary Doctor of Science degree from the University of South Dakota.
Business Week named Waitt one of America’s 50 most generous philanthropists due to his work with the Waitt Foundation. The Foundation funds partnerships and projects, sometimes in conjunction or collaboration with the Waitt Institutes, that seek a deeper understanding of human history and improve mankind’s knowledge through historical and scientific exploration.
Established in 1993, the Foundation initially focused on domestic violence prevention and community development, knowing that building stronger families and societies will help foster the vision of a better world. The creation of the Waitt Institutes in 2005—the Waitt Institute, and the Waitt Institute for Violence Prevention—has allowed the Foundation to broaden its program interests to the global community.
Waitt serves as the Chairman of the Founding Fathers campaign of the Family Violence Prevention Fund, just one of the efforts that he supports in the fight to prevent domestic violence. Waitt was appointed by Congress to serve on the Advisory Commission on Electronic Commerce and has served on numerous other corporate and philanthropic boards of directors, including the Advisory Council of the National Geographic Society and as Vice Chair of the Board of Trustees of the Salk Institute for Biological Studies.
On 15 Sept, 2016, the Waitt Foundation joined with the Wildlife Conservation Society (WSC), the blue moon fund (bmf) and the Global Environmental Facility (GEF) to commit a combined $48 million towards expansion of the world's marine protected areas (MPA). On 1 May 2008, the Salk Institute for Biological Studies announced the grant of $20 million from the Waitt Foundation to fund the creation of an Advanced Biophotonics Center. On 18 December 2008, the William J. Clinton Foundation released a list of all contributors. It included Theodore Waitt, who gave between US$10–25 million. On April 23, 2011, the Sioux City Public Museum had its grand opening. $4 million of its $13 million development budget was donated by the Waitt Foundation.
Waitt served as chairman of the Founding Fathers campaign of the Family Violence Prevention Fund; vice chairman of the board of trustees at the Salk Institute for Biological Studies; trustee of the National Geographic Society; founding member of Oceans 5; and board member of the Pristine Seas initiative.