[2][3] Cronin and co-researcher Val Logsdon Fitch were awarded the 1980 Nobel Prize in Physics for a 1964 experiment that proved that certain subatomic reactions do not adhere to fundamental symmetry principles.

[4][5][6][7][excessive citations] Cronin received the Ernest Orlando Lawrence Award in 1976 for major experimental contributions to particle physics including fundamental work on weak interactions culminating in the discovery of asymmetry under time reversal.

His father, James Farley Cronin, was a graduate student of classical languages at the University of Chicago.

After high school Cronin stayed in Dallas and obtained an undergraduate degree at SMU in physics and mathematics in 1951.

His teachers there included Nobel Prize laureates Enrico Fermi, Maria Mayer, Murray Gell-Mann and Subrahmanyan Chandrasekhar.

After obtaining his doctorate in 1955, Cronin joined the group of Rodney L. Cool and Oreste Piccioni at Brookhaven National Laboratory, where the new Cosmotron particle accelerator had just been completed.

After Cosmotron underwent magnet failure, Cronin and the Brookhaven group moved to Bevatron at the University of California, Berkeley during the first half of 1958.

[10] When he moved to Chicago, he began a long series of experiments on particle production at high transverse momentum.

In 1998 he joined the faculty at the University of Utah on a half-time basis to work on ultra-high-energy cosmic ray physics and to jumpstart the Pierre Auger Observatory project.