The brief answer is, yes, you need to cite your source each time you refer to it. If you have ten places you make use of a paper, be they quotations, justification of claims made, indications of further places providing supporting evidence, then each of these ten uses must be backed up by an inline citation. However, as Jeromy notes, this is not as onerous as it sounds, since if you write in a natural style and describe who carried out the work, then you only need to add the date in parentheses. The Chicago Manual of Style (CMoS) provides several other mechanisms to minimise the amount of text taken up by inline citations, which is important for readability.
Background on Chicago's author-date system
The current (16th) edition of the Chicago Manual of Style (abbrev. CMoS-16) gives extensive documentation on how its author-date citation style is defined and to be applied in chapter 15: the style is one of two supported citation styles, the other being the notes&bibliography approach, where citations are generally given in footnotes using the title of the work, rather than the date. Note that both the author-date and notes&bib citations styles are used in philosophy: Proc. Aristotelian Society, e.g., uses author-date, while Ethics uses notes&bib. The system described in the 16th ed. is a substantial simplification of that in the 15th edition of CMoS: make sure you refer to this edition.
The following citations might appear in the body of a text. I've put an example of using a citation possessively, which can help quite a bit in making citations blend naturally into text.
Strawson (1950)'s critique of the theory of descriptions put forward by Russell (1904) has generated a considerable literature (e.g., Donnellan 1960, 1978; Dummett 1973; Kripke 1977; Ludlow and Neale 1991). Ludlow (2005) provides an overview of this body of work.
Then there should be a references section at the end containing each cited work. I've given examples of works with multiple authors, two works by the same author, citations from a book as well as from journals. Note that titles of books and journals are italicised; titles of articles and book chapters are placed in quotation marks.
- Donnellan, Keith S. 1966. “Reference and Definite Descriptions.” Philosophical Review 77:281—304.
- ————————. 1978. “Speaker Reference, Descriptions, and Anaphora.” In P. Cole (ed.), Syntax and Semantics 9: Pragmatics. New York: Academic Press, 47—68.
- Dummett, Michael A. E. 1973. Frege: Philosophy of Language. Cambridge, MA: Harvard University Press.
- Kripke, Saul. 1977. “Speaker Reference and Semantic Reference.” In French, Uehling, and Wettstein (eds.), Contemporary Perspectives in the Philosophy of Language, Minneapolis: University of Minnesota Press, 6—27.
- Ludlow, Peter, and Stephen Neale. 1991. “Indefinite Descriptions: In Defense of Russell.” Linguistics and Philosophy 14:171—202.
- Ludlow, Peter. 2005. “Descriptions.” The Stanford Encyclopedia of Philosophy (Summer 2005 Edition), Edward N. Zalta (ed.). Retrieved from
- Russell, Bertrand. 1905. “On Denoting.” Mind 14:479—493.
- Strawson, Peter F. 1950. “On Referring.” Mind 59:320—334.