The Professional Career series (22.1 linear feet, 4 oversize boxes, and 306.94 MB) consists of eight subseries that document various aspects of Johnson's professional career. Material is dated from 1953-2014 and includes correspondence, notes, papers, photographic material, publications, and project and topical files.
Of particular note are four subseries—Johnson, Johnson, & Roy, Inc. (3.3 linear feet and oversize material), William J. Johnson Associates, Inc. (5.3 linear feet and digital material), Peter Walker, William Johnson, & Partners, Inc. (2.1 linear feet and oversize material), and NBBJ (1.1 linear feet and digital material)—that document Johnson's professional life. The bulk of the files in these subseries are project files that consist of one or more folders related to a specific project. Each subseries concludes with a "Correspondence/General Matters" file group consisting of files on various topics.
Because there is overlap between these subseries, researchers are encouraged to consult multiple subseries.