Timothy J. Clark completed his undergraduate studies at St John's College, Cambridge, he obtained a first-class honours degree in 1964. He received his PhD in art history from the Courtauld Institute of Art, University of London in 1973. He lectured at the University of Essex 1967–69 and then at Camberwell College of Arts as a senior lecturer, 1970–74. He taught at the University of California, Los Angeles in 1974–76. In 1976, he became a founding member of the Caucus for Marxism and Art of the College Art Association. Clark returned to Britain in 1976 when he was appointed professor and head of the Department of Fine Art at the University of Leeds. In 1980 Clark joined the Department of Fine Arts at Harvard University. In 1988 he joined the faculty at the University of California, Berkeley, where he held the George C. and Helen N. Pardee Chair as Professor of Modern Art until his retirement.

Clark is the author of a series of books on the social character and formal dynamics of modern art: The Absolute Bourgeois: Artists and Politics in France 1848-1851 (1973); Image of the People: Gustave Courbet and the 1848 Revolution (1973); The Painting of Modern Life: Paris in the Art of Manet and his Followers (1984); and Farewell to an Idea: Episodes from a History of Modernism (1999); as well as Afflicted Powers: Capital and Spectacle in a New Age of War (written with “Retort,” 2005); The Sight of Death: An Experiment in Art Writing (2006); Picasso and Truth: From Cubism to Guernica (2013); and a book accompanying an exhibition at Tate Britain, co-authored with Anne M. Wagner, Lowry and the Painting of Modern Life (2013).

In 1991 Clark was awarded the College Art Association's Distinguished Teaching of Art History Award. Notable students include Thomas E. Crow, Michael Kimmelman, John O'Brian and Jonathan Weinberg.