Eagleman was born in New Mexico to Arthur and Cirel Egelman, a physician and biology teacher, respectively. An early experience of falling from a roof raised his interest in understanding the neural basis of time perception. He attended the Albuquerque Academy for high school. As an undergraduate at Rice University, he majored in British and American literature. He spent his junior year abroad at Oxford University and graduated from Rice in 1993. He earned his PhD in Neuroscience at Baylor College of Medicine in 1998, followed by a postdoctoral fellowship at the Salk Institute.
Eagleman is currently adjunct associate professor at Stanford University and previously directed a neuroscience research laboratory at Baylor College of Medicine. He sits on boards of several arts organizations and is the youngest member of the board of directors of the Long Now Foundation. Eagleman is a Guggenheim Fellow, a Next Generation Texas Fellow, a Fellow of the Institute for Ethics and Emerging Technologies, and a council member on the World Economic Forum's Global Agenda Council on Neuroscience & Behavior. He was voted one of Houston's Most Stylish men, and Italy's Style fashion magazine named Eagleman one of the "Brainiest, Brightest Idea Guys" and featured him on the cover. He was awarded the Science Educator Award by the Society for Neuroscience. He has spun off several companies from his research, including BrainCheck, which develops portable cognitive testing and concussion detection, and NeoSensory, which uses sound-to-touch sensory substitution to feed data streams into the brain, as described in his 2015 TED talk.
Eagleman has been profiled in popular-press magazines such as the New Yorker, "The Atlantic", Texas Monthly, and Texas Observer, on pop-culture television programs such as The Colbert Report and on the scientific program Nova Science Now. Stewart Brand wrote that "David Eagleman may be the best combination of scientist and fiction-writer alive". Eagleman founded Deathswitch, an internet based dead man's switch service, in 2007.
As opposed to committing to strict atheism or to a particular religious position, Eagleman refers to himself as a possibilian, which distinguishes itself from atheism and agnosticism by studying the structure of the possibility space.
In 2015, Eagleman gave a TED talk which unveiled a method for using sound-to-touch sensory substitution to feed data streams into the brain. He spun off a company from his lab, NeoSensory, with offices in Houston and the Bay Area.
Eagleman's scientific work combines psychophysical, behavioral, and computational approaches to address the relationship between the timing of perception and the timing of neural signals. Areas for which he is known include temporal encoding, time warping, manipulations of the perception of causality, and time perception in high-adrenaline situations. In one experiment, he dropped himself and other volunteers from a 150-foot tower to measure time perception as they fell. He writes that his long-range goal is "to understand how neural signals processed by different brain regions come together for a temporally unified picture of the world".
Synesthesia is an unusual perceptual condition in which stimulation to one sense triggers an involuntary sensation in other senses. Eagleman is the developer of The Synesthesia Battery, a free online test by which people can determine whether they are synesthetic. By this technique he has tested and analyzed thousands of synesthetes, and has written a book on synesthesia with Richard Cytowic, entitled Wednesday is Indigo Blue: Discovering the Brain of Synesthesia. Eagleman has proposed that sensory processing disorder, a common characteristic of autism, may be a form of synesthesia
Eagleman has published extensively on what visual illusions  tell us about neurobiology, concentrating especially on the flash lag illusion and wagon wheel effect.
Neurolaw is an emerging field that determines how modern brain science should affect the way we make laws, punish criminals, and invent new methods for rehabilitation. Eagleman is the founder and director of the Center for Science and Law.
In 2015, Eagleman wrote and hosted The Brain with David Eagleman, an international television documentary series for which he was the writer, host, and executive producer The series debuted on PBS in 2015, followed by airings on the BBC in the United Kingdom and the SBS in Australia. The New York Times listed it as one of the best television shows of 2015. As of 2016, the series was nominated for an Emmy Award.
Eagleman served as the science advisor for the TNT television drama, Perception, which stars Eric McCormack as a schizophrenic neuropsychiatrist. In that role, Eagleman wrote one of the episodes, Eternity.
Eagleman's work of literary fiction, Sum: Forty Tales from the Afterlives, is an international bestseller published in 28 languages. The Observer wrote that "Sum has the unaccountable, jaw-dropping quality of genius", The Wall Street Journal called Sum "inventive and imaginative", and the Los Angeles Times hailed the book as "teeming, writhing with imagination". In the New York Times Book Review, Alexander McCall Smith described Sum as a "delightful, thought-provoking little collection belonging to that category of strange, unclassifiable books that will haunt the reader long after the last page has been turned. It is full of tangential insights into the human condition and poetic thought experiments... It is also full of touching moments and glorious wit of the sort one only hopes will be in copious supply on the other side." Sum was chosen by Time Magazine for their 2009 Summer Reading list, and selected as Book of the Week by both The Guardian and The Week. In September 2009, Sum was ranked by Amazon as the #2 bestselling book in the United Kingdom. Sum was named a Book of the Year by Barnes and Noble, The Chicago Tribune, The Guardian, and The Scotsman.
Eagleman's science book Incognito: The Secret Lives of the Brain is a New York Times bestseller and was named a Best Book of 2011 by Amazon, the Boston Globe, and the Houston Chronicle. Incognito was reviewed as "appealing and persuasive" by the Wall Street Journal and "a shining example of lucid and easy-to-grasp science writing" by The Independent. The book explores the brain as being a "team of rivals", with parts of the brain constantly "fighting it out" among each other.
In 2015, The Brain came out as a companion book to the television series The Brain with David Eagleman.
In 2016, Eagleman co-authored this Cognitive Neuroscience textbook with Jonathan Downar. The textbook is published by Oxford University Press.
In 2010, Eagleman published Why the Net Matters (Canongate Books), in which he argued that the advent of the internet mitigates some of the traditional existential threats to civilizations. In keeping with the book's theme of the dematerialization of physical goods, he chose to publish the manuscript as an app for the iPad rather than a physical book. The New York Times Magazine described Why the Net Matters as a "superbook", referring to "books with so much functionality that they're sold as apps". Stewart Brand described Why the Net Matters as a "breakthrough work". The project was longlisted for the 2011 Publishing Innovation Award by Digital Book World. Eagleman's talk on the topic, entitled "Six Easy Ways to Avert the Collapse of Civilization", was voted the #8 Technology talk of 2010 by Fora.tv.Brain and Behavior: A Cognitive Neuroscience Perspective, co-authored with Jonathan Downar, Oxford University Press, 2016.
The Brain with David Eagleman, a PBS television series, 2015.
The Brain: The Story of You, Canongate Books, 2015.
Incognito: The Secret Lives of the Brain, Pantheon Books, 2011
Why the Net Matters: How the Internet will save Civilization, Canongate Books, 2010.
Wednesday is Indigo Blue: Discovering the Brain of Synesthesia, co-authored with Richard Cytowic, 2009, MIT Press.
Sum: Forty Tales from the Afterlives, Pantheon Books, 2009. (Fiction)