Final answer:
Alexander Hamilton was the Federalist who advocated for a strong centralized government in Federalist No. 70, emphasizing the importance of unity and stability for the prosperity of the nation.
Step-by-step explanation:
The Federalist who wanted a strong centralized government focused on commerce and industry and who wrote the Federalist No. 70 was Alexander Hamilton. Hamilton, as a key figure among the Federalists, argued for a robust executive branch in the well-known Federalist Papers, advocating for the benefits a strong national government would bring in terms of diplomatic and domestic advantages. Hamilton, along with James Madison and John Jay, worked to assure the public that despite creating a strong government, the structure of checks and balances would prevent a rise to tyranny.