Bolza went on to supervise Bliss's Ph.D. thesis, The Geodesic Lines on the Anchor Ring, completed in 1900 and published in the Annals of Mathematics in 1902.

Bliss was a Preceptor at Princeton University, 1905–08, joining a strong group of young mathematicians that included Luther P. Eisenhart, Oswald Veblen, and Robert Lee Moore.

That Department was less distinguished under Bliss than it had been under E. H. Moore's previous leadership, and than it would become under Marshall Stone's and Saunders MacLane's direction after World War II.

In 1918, he and Oswald Veblen worked together in the Range Firing Section at the Aberdeen Proving Ground, applying the calculus of variations to correct shell trajectories for the effects of wind, changes in air density, the rotation of the Earth, and other perturbations.

Bliss set out the canonical formulation and solution of the problem of Bolza with side conditions and variable end-points.

Subsequent work on variational problems would strike out in new directions, such as Morse theory, optimal control, and dynamic programming.