He was close friends with the physicist Carl Anderson from an early age.

Both men attended California Institute of Technology together for bachelor's and graduate education and received their doctorates on the same day in 1930.

He was named Assistant Curator in the Division of Vertebrate Paleontology at the Smithsonian Institution in 1932.

Gazin served as President of the Society of Vertebrate Paleontology and was a Director of the American Geological Institute.

[1] Among his accomplishments, the Giant Ground Sloth of North America was discovered by Gazin, and has a specimen on display in the Smithsonian Natural History Museum.