Otis Dudley Duncan was born on December 2, 1921, in Nocona, Texas, the son of Otis Durant and Ola (Johnson) Duncan. He attended Oklahoma Agricultural and Mechanical College (now Oklahoma State University) from 1938-1940 and Louisiana State University in 1941, where he received his bachelor's degree. In 1942 he earned a master's degree from the University of Minnesota. He spent 1943 studying at the University of Iowa before moving to the University of Chicago, where he was awarded his doctorate in 1949. On January 16, 1954, he married Beverly Davis, a writer with whom he collaborated on numerous studies.

Duncan's career as an expert in social statistics began in 1948 as an assistant professor of sociology at Pennsylvania State College (now University). From 1950-1951, he taught at the University of Wisconsin at Madison. He served as an assistant professor of sociology at the University of Chicago from 1951-1956, as an associate professor of human ecology from 1957-...