Martin Whitman, who built a storied career and a venerated fund firm based on his own style of value investing, died Monday evening at the age of 93.

Whitman, who founded Third Avenue Management in 1986, adhered to a deep value style of investing, hunting for “cheap and safe” stocks. Whitman found these stocks via his focus on the balance sheet, rather than some of the other metrics laid out by Benjamin Graham and David Dodd, the deans of value investing.

In...