Clay was an honorary member of both the American Institute of Architects (AIA) and the American Society of Landscape Architects (ASLA) and was editor of Landscape Architecture Magazine from 1960 to 1985. He also was chairman of the jury that judged the design competition for the United States' Vietnam Veterans Memorial, was the Urban Affairs editor for the Louisville Courier-Journal, and provided a commentary segment, "Crossing the American Grain" which aired locally during National Public Radio's Morning Edition. In 1999, he was awarded the Olmsted Medal by ASLA. Clay also is a former president of the American Planning Association (formerly the American Society of Planning Officials) and was awarded an honorary doctorate by Emory University.
In an article from the July 2006 Landscape Architecture Magazine, editor J. William "Bill" Thompson noted that Clay "once forecast that the design profession with the best information was going to dominate the others –and he wasn't at all sure that landscape architecture had the capacity to generate the best information".
In 2009 the Congress for the New Urbanism (CNU) honored Clay with its Athena Award for his early work in naming and helping define the New Urbanism movement. Clay's 1959 article in Horizon Magazine, Metropolis Regained, critiqued the current highway dominated vision of cities and described the nascent rediscovery of the values and pleasures of the traditional city. Thirty five years before the creation of CNU, he identified the principles of a group he called the New Urbanists. "We believe in the city, they would say, not in tearing it down. We like open space, but hold that too much of it is just as bad as too little. We want that multiplicity of choice that the city has always offered, but is now in danger of losing," Clay wrote. "I can only say that all great movements start in murmurs and that I can hear murmurs."
Before Grady Clay was editor of LAM, most articles were written by professional landscape architects; during his tenure, many contributions were by professional writers without architecture credentials. He published Ian McHarg's ecological planning research, and covered areas that included use of native species for plantings, landscape sculpture and adventure playgrounds.
After 1939, Clay lived in Louisville, Kentucky, and was still actively writing and gardening. He was a founder of the Crescent Hill Community Association, a neighborhood association. Most of his professional papers went to the University of Louisville. His journals and other papers going back to 1939 are in the archives of the Loeb Library at Harvard.
Clay died in Louisville, on March 17, 2013, at the age of 96.
Clay's books include:
- Close-Up: How to Read the American City 1974
- Being a disquisition upon the origins, natural disposition and occurrences in the American scene of alleys ... a hidden resource 59 pages, 1978, ASIN B0006CY1F2
- Water and the Landscape (as editor), 193 pages, McGraw-Hill Education (February 1, 1979), ISBN 978-0-07-036190-4
- Right Before Your Eyes: Penetrating the Urban Environment, 241 pages, American Planning Association (October 1987), ISBN 978-0-918286-47-5
- Real Places: An Unconventional Guide to America's Generic Landscape. 322 p., 100 halftones, 16 line drawings. 8½ × 9¼ 1994, ISBN 978-0-226-10946-6
- Crossing the American Grain 2003, ISBN 978-1-884532-51-1
- "Noted Journalist, Urbanist Grady Clay Dead at 96". Retrieved 18 March 2013.
- July 2006 Landscape Architecture column discussing Clay
- Catalog entry from University of Louisville library
- author bio from Crossing the American Grain'