Kahn was a Chartered Financial Analyst and among the first round of applicants to take the CFA exam. He was a founding member of the New York Society of Security Analysts and the Financial Analysts' Journal. Kahn was also a former director of Teleregister Corp., Hugo Stinnes Co., Grand Union Stores, Kings County Lighting, West Chemical, and Willcox & Gibbs. He was the president of the New York City Job and Career Center and was a trustee emeritus of the Jewish Foundation for Education of Women.
In a magazine article in 2002, he was quoted as saying: "I'm at the stage in life where I get a lot of pleasure out of finding a cheap stock," adding that his research still pushed him to work evenings and weekends. His son Thomas, then and still currently President of Kahn Brothers Group, said, "My father continues to research ideas and talk to companies. One of the nice things about this business is that there's no mandatory retirement age, and you allegedly get wiser as you get older