Benjamin Franklin (1706-1790) was decidedly not a "Rebel Waiting for a Cause." For most of his life, he was a avid proponent of the British Empire, having lived for a time in England and eventually securing his son William (1731-1813) the post of Royal Governor of New Jersey in the 1760's, as Ben had influence with the Prime Minister at the time.
However, Franklin turned revolutionary after he was publicly humiliated at the "cockpit" in London for his actions in the Whatley Letter scandal in 1774 (see link below) which effectively ended his political and public life with Britain, although he had not done anything wrong.
Realizing that his own reputation in Britain was destroyed, and that reconciliation with the British was unattainable not only by himself but by any diplomat, he put forth his considerable efforts towards American Independence via an alliance with France.
As with all parsing of an individual's life prior to their entry into the political realm, there is complexity. Franklin's life is no different. Certainly, Franklin was not the first voice to demand Colonial political activism. Franklin's life was devoted to living out the traits from his Poor Richard's Almanack: "thrift, industry, and frugality." These do not lend themselves to rebellion and advocating a voice of dissent.
However, as Franklin's prominence in Colonial society became more pronounced and more evident, his leadership role and willingness to become more of a political force also increased. Franklin was not opposed to using his printing press to help publish documents that advocated the reexamination of political realities in the Colonies. As early as 1729 with the publication of A Modest Enquiry into the Nature and Necessity of a Paper Currency, Franklin demonstrated himself willing to serve as a voice of leadership in Colonial identity. He formed guilds and associations with other merchants such as the "Junta" that could be seen as political activism in its earliest stages. Franklin's leadership during the French and Indian War, advocating Colonial unity in support of England helped to move him into the realm of political leadership and guidance, something that would propel him as a major figure in the battle for Colonial independence.