Baltzell was born in Philadelphia, to a wealthy Episcopalian family. "Digby" attended St. Paul's School, an Episcopal boarding school in New Hampshire. He attended the University of Pennsylvania, where he was a member of St. Anthony Hall, and graduated in 1940. He served as a naval aviator during World War II, then earned his doctorate from Columbia University.
Raised in the Chestnut Hill section of Philadelphia, he had houses on Delancey Place in Philadelphia and in Wellfleet, Massachusetts. An expert historian of Social Register clubs, he was asked to join many of them. He chose to be a member of only one, the Franklin Inn Club in Philadelphia, where he was a frequent luncheon guest during the last years of his life.
He joined the faculty of sociology at the University of Pennsylvania in 1947. He was described as a dapper figure in tweed jackets and bow ties, popular in a slightly aloof way, but always courteous and accessible. He could often be seen pedaling an old one-speed bicycle between his Delancey Place home near Rittenhouse Square and Penn's West Philadelphia campus. Far more important to him than his personal preference for English clothes and for the ethos and manners of the gentleman was his conviction that aristocracy was necessary for the provision of leadership, both nationally and internationally. He felt that social stratification was inevitable, but that if the highest socio-economic levels were not accessible on the basis of merit (regardless of ethnic or racial background) society would degenerate into harmful caste-dictated divisions. His most productive years as an academic and social commentator corresponded to the actual relaxation of social barriers that took place in the late 1960s. It was apparent to students in his classes that he disdained the use of mathematical and statistical models as crutches to support sociological hypotheses. During the Vietnam War he once asked a class of predominantly male students the odds of being shot if one were sent into combat in Southeast Asia. After dismissing a few statistical responses from students, he gave the answer. "Fifty-Fifty," he declared. "Either you will or you won't." He dedicated one of his books to "all my undergraduate friends at the University of Pennsylvania, many of them grandsons of immigrants to the urban frontier, who, in spite of their possessing too many Jaguars and mink-coated mothers, have constantly been renewed by faith in the American Dream of unlimited opportunity".
He was elected an honorary member of the Philomathean Society, the University of Pennsylvania's literary and debating society, founded in 1813. He served as a judge for the now-legendary Philo v. Whig-Clio (Princeton University) debate of 1984, donning a London barrister's white wig and helping to determine the victor (Philo) in the debate "Should there be a Hell?" which was featured on National Public Radio's "All Things Considered" and in the Congressional Record.
Baltzell was appointed the Danforth Fellow at the Society for Religion in Higher Education of the Princeton Theological Seminary from 1967 to 1968, Charles Warren Research Fellow at Harvard University from 1972 to 1973, and Guggenheim Fellow from 1978 to 1979. He was a member of the American Sociology Association, the American Studies Association, and the Historical Society of Pennsylvania.
Baltzell retired in 1986, and became Emeritus Professor of History and Sociology. Baltzell's first wife, the artist Jane Piper, died in 1991. In 1994, he was elected a Fellow of the American Academy of Arts and Sciences.
He was survived by two daughters, Eve and Jan Baltzell; his second wife, Jocelyn Carlson Baltzell; and two stepdaughters Justina Carlson and Julie Carlson Groves. He was also survived by a brother, Dr. William Hewson Baltzell, IV, a niece (Virginia Baltzell) and two nephews.
A group of former students are raising funds to add a carved stone gargoyle in Digby's likeness to the University of Pennsylvania's Quadrangle dormitory before the 2015 centennial of his birth.
His family endowed a room in the St. Anthony Hall building at 3637 Locust Walk, which was renamed the "Digby Baltzell Library."Philadelphia Gentlemen: The Making of a National Upper Class (1958)
American Business Aristocracy (1962)
The Protestant Establishment: Aristocracy and Caste in America (1964)
Puritan Boston and Quaker Philadelphia: Two Protestant Ethics and the Spirit of Class Authority and Leadership (1979)
The Protestant Establishment Revisited (1991)
Judgment and Sensibility: Religion and Stratification (1994)
Sporting Gentlemen: Men's Tennis from the Age of Honor to the Cult of the Superstar (1995)