Final answer:
George Washington set important precedents for the executive branch of government as the first U.S. President, including the cabinet system and the two-term presidency.
Step-by-step explanation:
The individual who set important precedents for the executive branch of government was George Washington. As the first President of the United States, Washington established many roles and traditions that would shape the presidency moving forward, such as the cabinet system and the presidency limited to two terms, a precedent he set by refusing a third term. Although other figures like Thomas Jefferson, Alexander Hamilton, and Edmund Randolph played their respective roles in the early government, it was George Washington whose actions directly defined the executive branch's nature and role.