Early life and education
Krebs was born in Lansing, Iowa, the third child of William Carl Krebs, a Presbyterian minister and Louise Helen (Stegeman) Krebs. The family moved frequently due to the nature of his father's work, though they settled in Greenville, Illinois when Krebs was six and remained there until his father's unexpected death in 1933. Louise Krebs decided to move her family to Urbana, Illinois, where Krebs's elder brothers were attending the University of Illinois at Urbana-Champaign. Krebs attended Urbana High School, and enrolled at the University of Illinois at Urbana-Champaign in 1936. In his fourth year of study Krebs had decided to either pursue a higher degree in organic chemistry or study medicine. Receiving a scholarship to attend Washington University School of Medicine in St. Louis, he chose the latter.
The School of Medicine afforded Krebs the opportunity to train as a physician as well as to gain experience in medical research. Following graduation in 1943, he undertook an 18-month residency at Barnes Hospital in St. Louis and then went on active duty as a medical officer in the Navy. Krebs was discharged from the Navy in 1946 and was unable to immediately return to hospital work; he was advised to study basic science instead. He chose to study biochemistry and was postdoctoral fellow to Carl and Gerty Cori, working on the interaction of protamine with rabbit muscle phosphorylase. At the completion of his two years' study, Krebs decided to continue his career as a biochemist.