He was homeschooled by his parents, especially his mother, a Japanese American. He was diagnosed with ADHD and his parents declined to use the offered prescription of Ritalin. His younger sister, Maeghan, is also a child prodigy.
He spoke his first words at four months.  At the age of six months, he said to his pediatrician "I have a left ear infection" and learned to read at the age of ten months. When Michael was four, he was given multiple-choice diagnostic tests for the Johns Hopkins precocious math program. Without having studied specifically for the exam, Michael achieved a perfect score.
He attended San Marin High School in Novato, California, for one year, graduating at the age of six in 1990. He enrolled at Santa Rosa Junior College in Sonoma County, California, graduating at age 8 with an Associate of Science in Geology. He is listed in the Guinness Book as the world's youngest university graduate at the age of ten, receiving a bachelor's degree in anthropology from the University of South Alabama.
Research and teaching
He graduated from Middle Tennessee State University with a master's degree in biochemistry at the age of 14. His 118-page thesis is entitled "Kinetic Isotope Effects of Thymidine Phosphorylase". His research focused on the kinetics of a glycosyltransferase involved in nucleotide synthesis. For a while, he was the world's youngest postgraduate and the holder of several Guinness world records, but the master's degree record was broken by Tathagat Avatar Tulsi.
In October 2006, he became a finalist on the Mark Burnett/AOL quiz/puzzle game Gold Rush, winning $100,000. In November 2006, in front of a national audience on Entertainment Tonight, he went on to win the grand prize of an additional $1,000,000. Kearney was also a contestant on Who Wants to be a Millionaire? which aired on April 25 & 28, 2008. He left with $25,000.
Kearney was also a contestant on Million Dollar Password which aired on June 14, 2009, but did not pass the elimination round after losing in the tiebreaker.
- Kahlenberg, Richard (January 15, 1995). "The Smart Money Is on This Young Genius : Michael Kearney, 10, is the world's youngest college graduate and a cultural hero in Japan but finds a less enthusiastic response in the U.S.". Los Angeles Times. Retrieved 13 March 2011.
- Middle Tennessee State University, "The Record": "Veterinarian-to-be, age 9, set to receive her 'sheepskin' May 11", 2002 -[dead link]
- Kearney, K.J. and C.Y. (1998). Accidental Genius. Woodshed Press. ISBN 0-9628746-1-2. p. 24
- Burkdoll, Amy (August 8, 1998). "Latest accomplishment: 14-year-old genius gets his master's degree". Tuscaloosa News (AP). Retrieved 13 March 2011.