The majority of Marshall's papers document his career as a judge of the United States Court of Appeals for the Second Circuit, 1961-1965; as United States Solicitor General, 1965-1967; and as an associate justice of the Supreme Court of the United States, 1967-1991.

The Supreme Court File, 1967-1991, constitutes by far the largest part of the collection. Documenting Marshall's twenty four years as a Supreme Court justice, the series is divided into four subseries: General Correspondence, Case File, Dockets, and Miscellany. The Case File subseries, 1967-1991, consists of administrative and opinion files and are arranged chronologically by term, October through late June or early July, and therein numerically by docket number. Exceptions to this order include opinions and other documents generated after July which are usually filed in the previous court term, i.e., an opinion written in August 1979 is filed in the October 1978 term. As in the Solicitor General series, docket numbers of the appellate and in forma pauperis cases from 1967 to 1970 were supplemented by a two-digit prefix number supplied by Manuscript Division staff to assist in identifying the term in which cases are located.