Born in Newport, Rhode Island in 1727, William Ellery was the second in a family of four. Like his father, a prosperous merchant and influential political leader, he studied at Harvard College. Upon he his return home in 1747, he began to experiment with various jobs, eventually settling on law. He established a practice in 1770, and in the years that followed he became recognized for his work on numerous Rhode Island Patriotic committees.
Ellery arrived at the Continental Congress in May of 1776, and signed the Declaration of Independence in August of that same year. Later on in life, he held a congressional position (until 1786), and served as commissioner of the Continental Loan Office of Rhode Island (1786-1790). He died at the age of ninety-two in 1820, and was buried in Newport's Common Ground Cemetery.