He is best known as co-author, with Robert Venturi and Denise Scott Brown, of Learning from Las Vegas, one of the most influential architectural theory books of the twentieth century.

He was born in New Haven, Connecticut, where his father George Izenour, a theatre stage and lighting designer, taught at Yale University and later had a consulting firm.

After completing his degree at Yale, he ran the "Learning from Las Vegas" design studio for a time for Bob Venturi.

It was generally regarded at that time as a "non-city"; rather, as the outgrowth of "strip" development, along which were placed parking lots and separate frontages for gambling casinos, hotels, churches, and bars.

Virtually all architecture prior to the Modern Movement used such decoration to convey meaning, often profound but sometimes perfunctory, such as the signage on medieval shop fronts.

A split among young American architects occurred during the 1970s, with Izenour, Venturi, Robert A.M. Stern, Charles Moore and Allan Greenberg defended the book as "The Greys," and modernists Richard Meier, Peter Eisenman, John Heyduk, and Michael Graves wrote against its premises as "The Whites."

When Tom Wolfe published his critical book, From Bauhaus to Our House, Venturi, Scott Brown and Izenour were among those architects the author praised for their stand against heroic Modernism.

In 1979, continuing his studies into the relationship of architecture and pop culture, Izenour and fellow architect Paul Hirshorn published a monograph about the White Tower Hamburgers fast food chain.