He was educated at the University of Nebraska, obtaining a bachelor"s degree in 1893 and master"s in 1896. Lehmer was awarded his Doctor of Philosophy from the University of Chicago in 1900 for a thesis Asymptotic Evaluation of Certain Totient-Sums under the supervision of East. H. Moore.
He was promoted to professor at Berkeley in 1918 and continued to teach there until retiring in 1937. In 1903, he presented a factorization of Jevons" number (8,616,460,799) at the San Francisco Section of the American Mathematical Society, December 19, 1903. He published tables of prime numbers and prime factorizations, reaching 10,017,000 by 1909.
