Directors of the gallery include Bartlett H. Hayes, Jr. (1940–1969),[1][2] Christopher C. Cook (1969–1989), Jock Reynolds (1989–1998),[3] Adam D. Weinberg (1999–2003), Brian T. Allen (2004–2013), Judith F. Dolkart (2014–2019), and Allison N. Kemmerer (2021-).

Purchasing and generous gifts have added works by such artists as George Bellows, Alexander Calder, Stuart Davis, Arthur Dove, Marsden Hartley, Hans Hofmann, Edward Hopper, Knox Martin, Georgia O'Keeffe, Jackson Pollock, Frederic Remington, Charles Sheeler, Frank Stella, John Sloan, Benjamin West and Andrew Wyeth.

The Addison's collection of 7,500 photographs spans the history of American photography and includes in-depth holdings of key individual artists, such as Lewis Baltz, Walker Evans, Robert Frank, Eadweard Muybridge, Carleton Watkins, Margaret Bourke-White, and Ansel Adams.

In recent years, the Gallery has acquired significant contemporary works by Emery Bopp, Carroll Dunham, Kerry James Marshall, Joel Shapiro, and Lorna Simpson.

As of 2022[update], the collection comprises over 22,000 works in all media, including painting, sculpture, photography, drawings, prints, and decorative arts from the eighteenth century to the present.