His maternal grandmother Jane Goble Goss, one of the first female doctors, showed Hubbs how to harvest shellfish and other sea creatures.

Hubbs completed his studies at Stanford University, following particularly the ichthyologist Charles Henry Gilbert, a disciple of Jordan.

From 1917 until 1920 Hubbs served as the assistant curator of fish, amphibians, and reptiles at the Field Museum of Natural History in Chicago.

In 1927, while working at the University of Michigan, he received his Ph.D., writing his dissertation on The Consequences of Structural Modifications of the Developmental Rate in Fishes Considered in Reference to Certain Problems of Evolution.

In this role, he conducted research on the diverse inventory of regional fauna, mortality, water pollution, growth and predation.

From 1944 to 1969, Hubbs taught biology at the Scripps Institution of Oceanography at the University of California San Diego in La Jolla, where he replaced Francis Bertody Sumner.

During the summer of 1946, Errol Flynn, son of a marine biologist, offered Hubbs to accompany him during a cruise aboard his yacht, the Zaca.

The results weren't great but Hubbs discovered high levels of endemism of species of Guadeloupe.

At first, he studied the fish of the Great Lakes but after moving to La Jolla, he expanded his research to include marine mammals.

For his environmental protection work he received a gold medal of the San Diego Natural History Society.