Michael Dell was born in 1965 in Houston, to a Jewish family whose surname reflects the translation into English of the original German/Yiddish Thal ("valley" or "dale [q.v.]"; modern common-noun spelling Tal) upon the family's immigration to the United States. The son of Lorraine Charlotte (née Langfan), a stockbroker, and Alexander Dell, an orthodontist, Michael Dell attended Herod Elementary School in Houston. In a bid to enter Business early, he applied to take a high school equivalency exam at age eight. In his early teens, he invested his earnings from part-time jobs in stocks and precious metals.

In January 1984, Dell banked on his conviction that the potential cost savings of a manufacturer selling PCs directly had enormous advantages over the conventional indirect Retail channel. In January 1984, Dell registered his company as "PC's Limited". Operating out of a condominium, the Business sold between $50,000 and $80,000 in upgraded PCs, kits, and add-on components. In May, Dell incorporated the company as "Dell Computer Corporation" and relocated it to a Business center in North Austin. The company employed a few order takers, a few more people to fulfill them, and, as Dell recalled, a Manufacturing staff "consisting of three guys with screwdrivers sitting at six-foot tables". The venture's capitalization cost was $1,000.

Forbes estimates Dell's net worth as of April 2018 at $23.5 billion. Dell married Susan Lieberman on October 28, 1989, in Austin, Texas; the couple reside there with their four children.

In 1992, aged 27, he became the youngest CEO of a company ranked in Fortune magazine's list of the top 500 corporations. In 1996, Dell started selling computers over the Web, the same year his company launched its first servers. Dell Inc. soon reported about $1 million in sales per day from dell.com. In the first quarter of 2001, Dell Inc. reached a world market share of 12.8 percent, passing Compaq to become the world's largest PC maker. The metric marked the first time the rankings had shifted over the previous seven years. The company's combined shipments of desktops, notebooks and servers grew 34.3 percent worldwide and 30.7 percent in the United States at a time when competitor's sales were shrinking.

In 1999, Michael and Susan Dell established the Michael and Susan Dell Foundation, which focuses on, among other causes, grants, urban education, childhood health and family economic stability. In 2006, the foundation provided $50 million in grants to three health-related organizations associated with the University of Texas: the Michael & Susan Dell Center for Advancement of Healthy Living, the Dell Pediatric Research Institute to complement the Dell Children's Medical Center, as well as funding for a new computer science building at the University of Texas at Austin campus. In 2013, the foundation provided an additional $50 million commitment to establish the Dell Medical School at the University of Texas at Austin. Since 1999, the MSDF has committed $1.23 billion to non-profits and social enterprises in the United States, India and South Africa. Dell is also behind the founding of the Dell Jewish Community Campus in the North West Hills neighborhood of Austin.

In 2002, Dell received an honorary doctorate in Economic Science from the University of Limerick in honor of his investment in Ireland and the local community and for his support for educational initiatives.

In 1998, Dell founded MSD Capital L.P. to manage his family's Investments. Investment activities include publicly traded securities, private equity activities, and real estate. The firm employs 80 people and has offices in New York, Santa Monica and London. Dell himself is not involved in day-to-day operations. On March 4, 2004, Dell stepped down as CEO, but stayed as chairman of Dell Inc.'s board, while Kevin Rollins, then President and COO, became President and CEO. On January 31, 2007, Dell returned as CEO at the request of the board, succeeding Rollins.

By 2010, the foundation had committed more than $650 million to children's issues and community initiatives in the United States, India and South Africa. Today the foundation has over $466 million assets under management.

In 2012, the Michael and Susan Dell Foundation committed $50 million for medical education. The Dell Medical School began enrolling students in 2016.

Accolades for Dell include "Entrepreneur of the Year" (at age 24) from Inc. magazine; "Top CEO in American Business" from Worth magazine; "CEO of the Year" from Financial World, Industry Week and Chief Executive magazines. Dell also received the 2013 Franklin Institute's Bower Award for Business Leadership.

In 2014, he donated $1.8 million to the Friends of the Israel Defense Forces.

On October 12, 2015, Dell Inc. announced its intent to acquire the enterprise software and storage company EMC Corporation. At $67 billion, it has been labeled the "highest-valued tech acquisition in history". The acquisition was finalized September 7, 2016.

In 2017, in the wake of Hurricane Harvey, Dell, a Houston native, pledged $36 million to relief efforts.

In February 2018, it was reported that in 2014, Dell had paid $100.5 million for Manhattan's One57 penthouse, which still held the record for the most expensive home ever sold in the city.