John Mauchly, then chairman of the physics department of nearby Ursinus College, was a student in the summer electronics course, and the following fall secured a teaching position at the Moore School.

Mauchly's proposal for building an electronic digital computer using vacuum tubes, many times faster and more accurate than the differential analyzer for computing ballistics tables for artillery, caught the interest of the Moore School's Army liaison, Lieutenant Herman Goldstine, and on April 9, 1943, was formally presented in a meeting at Aberdeen Proving Ground to director Colonel Leslie Simon, Oswald Veblen, and others.

A contract was awarded for Moore School's construction of the proposed computing machine, which would be named ENIAC, and Eckert was made the project's chief engineer.

Both Eckert and Mauchly left the Moore School in March 1946 over a dispute involving assignment of claims on intellectual property developed at the University.

In 1968, "For pioneering and continuing contributions in creating, developing, and improving the high-speed electronic digital computer", Eckert was awarded the National Medal of Science.

[9] Eckert's contention that von Neumann improperly took credit for devising the stored-program computer architecture was supported by Jean Bartik, one of the original ENIAC programmers.