"[4] He was born in Waterville, Maine to Ella Phoebe Marston and Howard Calvin Morse in 1892.

He wrote his PhD thesis, Certain Types of Geodesic Motion of a Surface of Negative Curvature, under the direction of George David Birkhoff.

That year, he accepted a position at the Institute for Advanced Study in Princeton, where he remained until his retirement in 1962.

[7] He spent most of his career on a single subject, now known as Morse theory, a branch of differential topology that enables one to analyze the topology of a smooth manifold by studying differentiable functions on that manifold.

Morse originally applied his theory to geodesics (critical points of the energy functional on paths); these techniques were used in Raoul Bott's proof of his periodicity theorem.