He developed a strong fascination with chemistry after visiting the DuPont exhibit at the Century of Progress World's Fair in Chicago in 1933.
He left the school as a sophomore and enlisted in the United States Army Air Corps, serving as a meteorologist in Labrador.
He rose through the ranks and had assignments that included the first discovery of oil in Saudi Arabia, made in 1938, for which Keller received a replica of the sword of Mohammed as a gift.
Keller had originally been reluctant to join the wave of mergers spreading through the industry based on his analysis that the firm could acquire new oil reserves at lower cost through exploration and drilling, rather than by purchasing competitors.
[1] In August 1988, Chevron named Kenneth T. Derr as chairman to succeed Keller, who would be reaching the mandatory retirement age of 65.