Born in Los Angeles, California, Fox graduated from the University of California in 1933 and earned his doctorate degree at the California Institute of Technology in 1940. Throughout his career, Fox taught at institutions in Florida and became associated with the National Aeronautics and Space Administration (NASA) after 1960. Fox pursued questions on the origins of life, but unlike other proponents of evolutionary theory who approached the question from a biochemical standpoint, Fox's approach was biological.

Fox asserted that a mixture of amino acids subjected to intense heat (a scenario in which the earth formed with a steaming ocean and exposed rocks) becomes a protein-like polymer. Fox named these polymers "proteinoids," or "coacervates." When dissolved in water, they form tiny spheres that share some properties with cells, including a double membrane and the ability to carry on simple chemical reactions. Adding more proteinoids to water will cause the spheres to combine, grow, and divide. Fox speculated from this evidence that the earliest cells were formed through this process. It has also been suggested that the formation of cells and nucleic acids may have paralleled each other and combined at some point, and that the advent of nucleic acids did not come about through proteinoids. Fox's theory is currently a subject of ongoing research throughout the scientific community.