Little is known conclusively about Johnson since he moved so frequently throughout Baltimore and its Fells Point neighborhood, according to Census records. Scholar J. Hall Pleasants surmises that Johnson was probably once a slave, a house servant of a portrait painter, to Polk or Charles Willson or Rembrandt Peale.

Of his 13 known works in existence, nine of the 13 paintings of children or of families with children, so they can be dated by the life dates of the children and their approximate ages when they sat for the portrait. Pleasants has analyzed Johnson's handling of his subjects and style and discovered the following characteristics: there is a "peculiar rigidity" of arms, hands, legs and feet; the subjects' faces are shown in three-quarter view, their eyes directed upward and their mouths drawn together tightly with no facial expression; the subjects often hold objects, such as book, riding crops, letters, basket, parasol, pencil, sextant, fruit or cake; brass tacks were used in upholstered settees or chairs of Sheraton type; the backgrounds of his compositions are dark and sombre; and dark or red curtains are shown. Furthermore, Pleasants associates Johnson's style with that of the Peale-Polk family of portraitists for its hard, linear, well-executed and attractive painting. Charles Peale Polk's work bears the most striking similarities in terms of the stiff handling of legs and arms, scarcity of modeling and two-dimensionality. Polk and Johnson also both applied paint sparingly.
Taught By: possibly Charles Peale Polk
Art-related Employment: painter
Other Employment: blacksmith?
Selected References: Dean, Mary A. [et al.]. 350 Years of Art & Architecture in Maryland (College Park : Art Gallery, and Gallery of the School of Architecture, University of Maryland), 1984.
Pleasants, J. Hall. An Early Baltimore Negro Portrait Painter, Joshua Johnston. (Windham, CT: Walpole Society), 1940.
Pleasants, J. Hall. Two Hundred and Fifty Years of Painting in Maryland (Baltimore: Baltimore Museum of Art), 1945.
Other Publications: American Paintings: An Illustrated Catalogue. National Gallery of Art, Washington, 1992.
Chotner, Deborah, with contributions by Julie Aronson, Sarah D. Cash, and Laurie Weitzenkorn. American Naive Paintings. The Collections of the National Gallery of Art Systematic Catalogue. (Washington, D.C., 1992: 234-235, repro. 234.
Perry, Mary Lynn. "Joshua Johnson: His Historical Context and His Art." M.A. thesis. George Washington University, Washington, 1983: iii, 94, 96, 126, 128-131, 152, 212-213.
Weekley, Carolyn J. [et al.] Joshua Johnson: Freeman and Early American Portrait Painter ( Williamsburg, Va.: Abby Aldrich Rockefeller Folk Art Center & Baltimore: Maryland Historical Society), 1987.
Maryland Institutions Holding Artworks: Baltimore Museum of Art (painting); Maryland Historical Society
Multiple-Artist Exhibitions: Sharing Traditions: Five Black Artists in Nineteenth-Century America, traveling exhibition organized by SITES, 1985-1988.
American Naive Paintings from the National Gallery of Art, traveling exhibition 1993-1998.