John Marshall was born in a log cabin on the Virginia frontier on Sept. 24, 1755, the first of 15 children. He was the son of a land surveyor who had amassed a substantial library of books, and as a child, Marshall was encouraged to read extensively.
As a young man he served as a captain in the Continental Army, and saw action in several battles, including Brandywine and Monmouth. While still serving in the military he studied law part-time at William and Mary College. The course of lectures he attended would be his only formal legal education. He was admitted to the Virginia bar in 1780, and entered political life a few years later, winning election to the Virginia Legislature in 1782.
Marshall earned a reputation as a very good lawyer who could think on his feet. And he also became known for arguing forcefully that Virginia should ratify the Constitution. At the 1788 Constitutional Convention in Virginia he defended Article III, which deals with the judiciary.
Marshall contemplated several offers to serve in the Washington and Adams administrations. He declined service as Attorney General for Washington; he declined positions on the Supreme Court and as Secretary of War under Adams. At Washington's direction, Marshall ran successfully for a seat in the U.S. House of Representatives but his tenure there was brief. Adams offered Marshall the position of Secretary of State, which Marshall accepted. When Oliver Ellsworth resigned as Chief Justice in 1800, Adams turned to the first Chief Justice, John Jay, who declined. Federalists urged Adams to promote Associate Justice William Paterson to the spot; Adams opted for Marshall.
Despite the apparently hasty circumstances of Marshall's nomination to the Supreme Court, he would be the longest serving Chief Justice in American history, holding the position for 34 years.
His influence on the Court was profound. When Marshall took office the judiciary was considerably weaker than the other two branches of the government, as the Constitution gave little direction to the Supreme Court. But under Marshall's guidance the Supreme Court became the powerful institution it has remained.
Marshall died on July 6, 1835. His death was marked with public displays of grieving, and in Philadelphia the Liberty Bell cracked while it was being rung in tribute to him.
Though Marshall was largely self-taught in the law, and his appointment to the Supreme Court seemed to be a spur-of-the-moment decision, he has been proclaimed "The Great Chief Justice."
Source: www.oyez.org, about.com