He went to Columbia University, New York, where he received a master's degree in Electrical Engineering and a Ph.D. in High Energy Physics, (sponsor J. Steinberger).

Modis carried out research in particle physics at Brookhaven National Laboratories and CERN before moving to work at Digital Equipment Corporation for more than a decade as the head of a management science consultants group.

[12] He is also the founder of Growth Dynamics,[13] a Swiss-based organization specializing in business strategy, strategic forecasting and management consulting.

[14] He has published about one hundred articles in scientific and in business journals, as well as ten books: Predictions, Conquering Uncertainty, An S-Shaped Trail to Wall Street (treating the New York Stock Exchange as an ecosystem), Predictions: 10 Years Later, Bestseller Driven, Natural Laws in the Service of the Decision Maker, Decision-Making for a New World, An S-shaped Adventure: "Predictions" 20 Years Later, Fortune Favors the Bold: A Woman’s Odyssey through a Turbulent Century,[15] and Science with Street Value: A Physicist's Wanderings off the Beaten Track.

Fortune Favors the Bold: A Woman’s Odyssey through a Turbulent Century has been translated into Greek and published under the title ΘΕΟΔΟΣΙΑ.