Charles Jencks was born on 21 June 1939 in Baltimore, Maryland.

His parents were Gardner Jencks, a pianist and composer, and Ruth (nee DeWitt Pearl). He took at BA in English Literature at Harvard University (1961) and then a BA and MA at Harvard Graduate School of Design (1965) He received a PhD from London University in 1970 for his thesis "Modern architecture: the tradition since 1945" which led to a series of articles in Arena and to the publication Modern Movements in Architecture (1972). From 1961 to 1973 he was married to Pamela Balding and had two sons, Justin and Cosmo. He married Maggie Keswick Jencks and had two children, John and Lily. Maggie died in 1995. In 2006 he married Louisa Lane Fox . He died on 13 October 2019.