He was Professor of Physical Oceanography at Harvard University and the Massachusetts Institute of Technology (MIT).
[3] His family were long-time members of the New York Yacht Club and his uncle, Charles Oliver Iselin, competed in the America's Cup.
[2] He served as the Assistant Curator of Oceanography at Harvard University's Museum of Comparative Zoology from 1929 to 1948.
[3] In 1926, Columbus O'Donnell Iselin led an expedition aboard the schooner "Chance" that combined maritime exploration with scientific research along the coasts of Newfoundland and Labrador to Cape Chidley.
The expedition collected botanical specimens, sampled plankton, and conducted hydrographic stations perpendicular to the coast.
Iselin later documented the voyage and its findings in a private publication titled "The Log of the Schooner Chance.