Dell had his first encounter with a computer at the age of 15 when he broke down a brand new Apple II computer and rebuilt it, just to see if he could. Dell attended Memorial High School in Houston where he did not excel scholastically. After graduating high school, he attended the University of Texas at Austin but abandoned that idea when he experienced early success in the area of computers and technology.

While at the University of Texas at Austin, he started a computer company called PC's Limited in his room . The company became successful enough that, with the help of an additional loan from his grandparents, Dell dropped out of college at the age of 19 to run PC's Limited, which later became Dell Computer Corporation, then ultimately Dell Inc.

Over time, and despite a number of setbacks (including laptops that caught on fire in 1993, temporarily losing the consumer market to Gateway in the mid 1990s, and others), Dell survived the race to become the most profitable PC manufacturer in the world, with sales of $49 billion and profits of $3 billion in 2004. As Dell expanded its product line to more than computers, shareholders voted to rename the corporation Dell, Inc. in 2003.

In 2002 he received an Honorary Doctorate in Economic Science from the University of Limerick, in honor of his investment in Ireland and the local community along with his support for educational initiatives.

On May 15, 2006, The University of Texas at Austin announced a $50 million grant from the Michael and Susan Dell Foundation to "bring excellence in children's health and education to Austin".

As of 2007, Forbes estimates Michael Dell's net worth at $15.8 billion, making him the 30th richest person in the world and the 9th richest American.