He began his undergraduate studies at the Massachusetts Institute of Technology in 1942, but left after one year, taking up a position as first lieutenant in the United States Army Air Forces during World War II, during which he taught about radar systems.

He then began graduate studies at Columbia University, under the supervision of Abraham Wald and Jacob Wolfowitz, receiving his Ph.D. in mathematical statistics in 1952.

[5][7] He waged what he called a "limited educational campaign" to highlight a choice beyond the two major parties,[8] acknowledging that his prior probability of winning the election was zero.

[7] During the early 1970s, Kiefer was on a committee offering views to Cornell's board of trustees regarding socially responsible investing.

However, he also made significant contributions to other areas of statistics and optimization,[11] including the introduction of golden section search (his master's thesis work) the Dvoretzky–Kiefer–Wolfowitz inequality and the Bahadur-Ghosh-Kiefer representation (with R. R. Bahadur and J. K.