The title of Tilly's 1984 book Big Structures, Large Processes, Huge Comparisons is characteristic of his particular approach to social science research.

[5][6] Tilly was a teaching assistant to Pitirim Sorokin, who along with Talcott Parsons and George C. Homans was considered by many in the profession to be among the world's leading sociologists.

He is considered a major figure in the development of historical sociology, the early use of quantitative methods in historical analysis, the methodology of event cataloging, the turn towards relational and social-network modes of inquiry, the development of process- and mechanism-based analysis, as well as the study of: contentious politics, social movements, the history of labor, state formation, revolutions, democratization, inequality, and urban sociology.

At Columbia, along with Harrison White, Tilly played a key role in the emergence of the New York School of relational sociology.

[13] In 1968 Tilly presented his report on European collective violence to the Eisenhower Commission, a body formed under the Johnson administration to assess urban unrest amidst the Civil Rights Movement.

[15] Tilly outlined the distinctive approach he would use in his research on the state and capitalism in Big Structures, Large Processes, Huge Comparisons (1984).

[19] More substantively, Tilly sketched a research program focused on two broad macro processes, capitalism development and the formation of modern states.

[28][29] As a critic of government intentions, Tilly “warns against the contractual model”,[30] with the belief that states of war are “our largest examples of organised crime”.

[29] On Tilly’s perspective, Stanford historian David Laboree says there are similarities between the collective monetary actions and enemy-related dealings of kings and pirates; the state’s legitimacy comes from convincing residents that there is more value in protection than the taxes being commandeered.

[31] As summarized by Prof. Mehrdad Vahabi of Tilly’s belief, the role of the state is protective in enhancement of production and predatory by way of “coercive extraction”.

[32] In the pre-1400s era predating an understood national budget, the primary revenue collection method of European “commercialized states” was through “tribute, rents, dues, and fees”.

[28][29] Tributes were extracted from defeated opponents, and a surviving political organization inevitably formed from necessary tax collection and enforcement.

[39] An article that examines pre- and post- French Revolution Europe that is in support of Tilly’s explanation of war as a dominant factor of state formation admits that there exist several critiques.

[41] Castellani writes that Tilly fails to account for “improvement of artillery…[and] the expansion of commerce and the production of capital” as other significant factors in state formation outside of pure vanquish.

to hold a Eurocentric syntax, as such a monopolization did not take place in the post-colonial world due to the heavy interference of foreign actors.

[57] The conference had presentations from notable sociologists including: Craig Calhoun, Harrison White, Doug McAdam, Immanuel Wallerstein, William Sewell, Jack Goldstone, Sidney Tarrow, Barry Wellman and Viviana Zelizer.

[59] The latter was edited by Andreas Koller, and included contributions by George Steinmetz, Neil Gross, Jack A. Goldstone, Kim Voss, Rogers Brubaker, Mustafa Emirbayer, and Viviana Zelizer.

In 2010, the journal Theory and Society also published a special issue on "Cities, States, Trust, and Rule" dedicated to the work of Tilly.