Jack Ryan is a significant character in The Hunt for Red October (1984; see separate entry), The Cardinal of the Kremlin (1988; see separate entry) and Clear and Present Danger (1989; see separate entry).

Clancy repeats several of his characters in his novels. Submariner Bart Mancuso, FBI agent Dan Murray, CIA Director Judge Moore, and assistant director Admiral Greer reappear often. Patriot Games explains how some of their relationships developed and how Ryan came to be both a pencil-pusher and a man of action.

The repetition of the characters creates continuity between the novels; The Cardinal of the Kremlin and Clear and Present Danger, in particular, make frequent allusions to the other novels.