Tom Demarco was born in Hazleton, Pennsylvania. Tom DeMarco received a BSEE degree in Electrical Engineering from Cornell University, a M.S. from Columbia University and a diplôme from the University of Paris at the Sorbonne.

DeMarco started working at Bell Telephone Laboratories in 1963, where he participated in ESS-1 project to develop the first large scale Electronic Switching System, which became installed in telephone offices all over the world. Later in the 1960s he started working for a French IT consulting firm, where he worked on the development of a conveyor system for the new merchandise mart at La Villette in Paris, and begin 1970s on the development of building on-line banking systems in Sweden, Holland, France and New York.

In the 1980s along with Tim Lister,Stephen McMenamin, John F Palmer, James Robertson and Suzanne Robertson, he founded the consulting firm "The Atlantic Systems Guild" in New York, where they initially shared offices with Dorset House publisher firm of Edward Yourdon. Their company developed into a New York- and London-based consulting company specializing in methods and management of software development.

DeMarco has lectured and consulted throughout the Americas, Europe, Africa, Australia and the Far East.

He is a member of the ACM and a Fellow of the IEEE. He lives in Camden, Maine, and is presently both a principal of The Atlantic Systems Guild, and a fellow and Senior Consultant of the Cutter Consortium. DeMarco was the 1986 recipient of the Warnier Prize for "lifetime contribution to the field of computing", and the 1999 recipient of the Stevens Award for "contribution to the methods of software development".

In his spare time, he is an Emergency medical technician, certified by his home state and by the National Registry of EMTs, and a founding member of The Penobscot Compact, a business-education partnership operating under the auspices of the Maine State Aspirations Program.

Tom DeMarco's particular areas of interest are project management, change facilitation, and litigation of software-intensive contracts.

DeMarco has authored over nine books and 100 papers on project management and software development. A selection:

• 1979. Structured Analysis and System Specification. Prentice Hall, ISBN 0138543801
• 1986. Controlling Software Projects: Management, Measurement, and Estimates. Prentice Hall, ISBN 0131717111
• 1987. Productive Projects and Teams. With Timothy Lister. Dorset House. ISBN 978-0932633439
• 1997. The Deadline: A Novel About Project Management. Dorset House.
• 2001. Slack, Getting Past Burnout, Busywork, and the Myth of Total Efficiency.
• 2003. Waltzing with Bears: Managing Risk on Software Projects. With Tim Lister. Dorset House in March, 2003.
• 2008. Adrenaline Junkies and Template Zombies: Understanding Patterns of Project Behavior. With Peter Hruschka, Tim Lister, Suzanne Robertson, James Robertson, Steve McMenamin. ISBN 978-0932633675
• 2009. "Software Engineering: An Idea Whose Time Has Come and Gone?". IEEE Software, Viewpoints. July/August 2009. pages 94—95.