[6] Elledge initially ignored life science subjects, until he attended biology and genetics courses on exchange to the University of Southampton, England, during his third (or junior) year.
He took biochemistry courses after returning to Illinois,[7] which prompted him to study PhD in biology at the Massachusetts Institute of Technology (MIT) after obtaining his BSc in 1978.
[15] Elledge's research spans multiple areas, including cell cycle, DNA repair, and detection of virus from blood.
Elledge accidentally[16] discovered the RNR2 gene and protein in yeast, which belongs to the family of ribonucleotide reductase, and found that its expression increases when DNA is damaged.
[18] Over the next decade, he continued the search for genes and proteins involved in the DNA damage response pathway in yeasts and humans.
In parallel and independently from Bert Vogelstein's group, he discovered and characterized p21, a cyclin-dependent kinase inhibitor protein that blocks G1/S transition.
[27] In 2015, Elledge's group developed VirScan, a platform that detects viral infection in patients from a small amount of blood.