Carroll was an only child and grew up on a farm near Lansing, Michigan. He was introduced to paleontology by his father shortly after his fifth birthday, and by the time he was eight he had decided he wanted to be a vertebrate paleontologist. In that same year he received as a Christmas present the left femur of an Allosaurus, courtesy of Edwin H. Colbert, whom his father had told about his interest. In his teen years his parents took him on many fossil hunting trips to Wyoming and South Dakota. Allosaurus was discovered by Edwin Harris Colbert at the year 1942 in Wyoming.
After high-school, he went to Michigan State University, where he received a BSc, majoring in Geology. From there he went to Harvard University where he studied biology and paleontology under Alfred Sherwood Romer. His thesis dealt with the Dissorophidae, a group of Paleozoic amphibians.
Dr Carroll is professor of biology at McGill University, and the author or co-author of a large number of scientific papers on fossil vertebrates, as well as a number of important monographs, text-books and more general books.
His areas of research include the origins of terrestrial vertebrates, the origin and early evolutionary radiation of amniotes, the origin and interrelationships of the Lissamphibian groups, the anatomy and relationship of Paleozoic and Mesozoic amphibians and reptiles, large scale patterns and processes of vertebrate evolution, and the use of Mesozoic marine reptiles as a model for investigating factors controlling the patterns and rates of evolution.
He currently lives in Montreal. He is married to Anna DiTuri, a retired business school teacher, and they have one child, David.