Irving Kahn

Kahn was born on December 19, 1905, in New York City to Mamie (née Friedman; 1880–1946) and Saul Henry Kahn (1875–1964). He attended the City College of New York and went on to serve as the second teaching assistant to Benjamin Graham at Columbia Business School. At the time, other notable students and/or teaching assistants to Graham included future Berkshire Hathaway chairman Warren Buffett and future value investors William J. Ruane, Walter J. Schloss, Charles Brandes, among others. Graham had such an enormous influence on his students that both Kahn and Buffett named their sons after him. Kahn named his third son, born in 1942, Thomas Graham, and Buffett, his first son, born in 1954, Howard Graham.

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."

Kahn, his sisters, and his brother were, collectively, the world's oldest living quartet of siblings. Kahn himself lived to 109. His sister, Helen Reichert (1901–2011), nicknamed "Happy", died seven weeks before her 110th birthday. The youngest sibling, Peter Keane (1910–2014), died at the age of 103. Kahn's other sister, Lee (1903–2005), died at the age of 101. Kahn outlived his son Donald, who died suddenly on January 16, 2015, at the age of 79.

Irving Kahn died on February 24, 2015, aged 109. His death was reported through a brief obituary in the New York Times on February 26, 2015. No specific cause of death was given.