Was Benjamin Franklin a federalist?

Franklin was a federalist (small f) in the sense of supporting the new constitution. He was central to the writing and formulation of the original Articles of Confederation. The articles were based on the Law of the Great Peace of the Iroquois Confederacy, the oldest written constitution in the world. Franklin had been commissioner (ambassador) to the Iroquois.
During the drafting of the Constitution, he played a very small role. He was very elderly and had to be carried into the convention. We have no evidence that he spoke during the debates.
Franklin's chief role was afterward. He owned most of the newspapers and magazines in the US, making him an early media tycoon. He refused to allow any criticism or debate on the Constitution during its ratification, only support. Other papers that came out against the Constitution faced a boycott by wealthy advertisers wanting it ratified. Many went out of business.
Franklin was not a member of the Federalist Party formed in 1792, at the earliest. Franklin died in 1790.