De Cecco was born in Erie, Pennsylvania. He studied at Allegheny College, where he took his degree in biology in 1946. He continued his studies at the University of Pennsylvania, where he received a masters and doctorate in English and Modern European History. He has also conducted post-doctoral studies in psychology at Wayne State University and later at Michigan State University, where he taught from 1955 to 1960, leaving to escape the widespread purges of homosexuals. De Cecco has been a member of the Psychology Department at San Francisco State University (SFSU) since 1960 and also taught at Columbia University. Author of about ten books, De Cecco is perhaps best known as the editor of the long-running Journal of Homosexuality, a post he has held since 1977.