Final answer:
James Madison, known as the Father of the Constitution played the most significant role in planning and writing the Virginia Plan.
Step-by-step explanation:
The delegate who played the biggest role in planning and writing the Virginia Plan was James Madison. Known as the "Father of the Constitution Madison's contributions to shaping the basic structure of the U.S. government were significant. His plan proposed representation in the legislative branch based on population, and he was willing to create a bicameral legislature as a compromise. His insights were instrumental in framing the Bill of Rights as well.