Keith Robertson was born on May 9, 1914 in Dows, Iowa. He joined the Navy in 1931, and served as a radioman on a destroyer. Later, he attended the United States Naval Academy, graduating with a B.S. degree. He attributed his initial decision to study at the Academy to a "fanatical aversion to washing dishes." He said, "When I discovered that midshipmen at the United States Naval Academy did not wash dishes but were gentlemen by act of Congress, I promptly applied for entrance." Robertson served in World War II as captain of a destroyer. He was awarded five battle stars. He retired from the service as a captain in the United States Naval Reserve.
Robertson published his first book, Ticktock and Jim in 1948. His writing career spanned 40 years. As a member of the Rutgers University Council on Children's Literature, he was active in encouraging aspiring authors.
He was married to Elizabeth Woodburn Robertson, a rare-book dealer, and had four children. He died in Hopewell, New Jersey on 23 September 1991, aged 77.
Keith Robertson is best known for the five books of the Henry Reed series, beginning in 1958 with Henry Reed, Inc. which won the William Allen White Children's Book Award in 1961. Another Henry Reed book, Henry Reed's Baby-Sitting Service also won this award, along with the Pacific Northwest Library Association Young Readers’ Choice Award, in 1969. The Henry Reed series was illustrated by Robert McCloskey.
Keith Robertson used the pseudonym Carlton Keith for his six murder mysteries.