Irving Kahn, who made his first stock trade in June 1929 — turning a tidy profit from the stock market crash four months later — and persevered for more than eight decades to become Wall Street’s oldest living active professional investor, died on Tuesday at his home in Manhattan. He was 109.

His son Thomas confirmed his death.

A disciple and later partner of Benjamin Graham, the contrarian advocate of “value investing,” Mr. Kahn would go on to work at Abraham & Company and Lehman Brothers, which he left in 1978 to open Kahn Brothers Group with two of his sons, Alan and Thomas. When he died, he was chairman of Kahn Brothers, a privately owned investment advisory and brokerage firm, which manages $1 billion through its subsidiaries.

He was also the last surviving member of what had been described as the oldest living sibling quartet. One sister, Lee, died in 2005 at the age of 101. Another sister, Helen Reichert, was seven weeks shy of her 110th birthday when she died in 2011. Their younger brother, Peter Keane, died last year after turning 103.

Until late last year, Mr. Kahn was still commuting by taxi to his Midtown office from his Upper East Side apartment three days a week.